Proven Industries vs Ft. Knox Coupler Locks

Buy the Proven Model 2516 if you want to know what you are getting. Proven publishes its materials, offers a documented ladder of cylinders up to Medeco and Abloy, maintains a coupler index, and will identify fitment from photographs you email them. It is the better-documented product, and in a category where almost nobody publishes anything, that counts.

Buy the Ft. Knox lock if a replaceable cylinder is worth more to you than published specifications. Its surround hasp takes a separate puck lock, so the cylinder is a component you choose, upgrade and replace — and it carries a limited lifetime warranty, which Proven does not publish at all.

The thing to understand before either purchase: on both locks, the cylinder is a separate decision from the lock, and on both it costs extra. Proven itemises it as an upgrade. Ft. Knox itemises it as a puck lock sold separately. The headline price of either is not the price of a lock you would want.

Specification by specification

Specification	Proven 2516	Ft. Knox Curt Style
Cylinder Type Not on quality — Proven offers better cylinders. On architecture: a separate puck can be replaced or upgraded later, a built-in one cannot	7-pin tubular (Cobra) as standard. Proven disc detainer, Medeco M3 and Abloy cylinders are paid upgrades, not the default	Separate puck lock, not built in. Ft. Knox offers Trimax, Cobra-Sidewinder and Abloy Sentry cylinders in its own aluminium and steel puck bodies Better
Material Proven names the alloy and grade. Ft. Knox says welded steel and publishes no gauge on its own pages	Billet 6061 aluminium or solid 303 stainless steel, depending on option Better	Welded steel with reinforced hinges and hinge pins. Ft. Knox does not publish a gauge on its own product pages; retail listings state 3/16 in cold-rolled steel
Country Of Origin Proven states majority USA manufacture. Ft. Knox is Tulsa-based but does not state where its locks are made	Majority manufactured in the USA, per Proven Industries Better	Not stated on Ft. Knox's own pages. The company is based in Tulsa, Oklahoma, and its retail listings state Made in USA
Warranty A published limited lifetime term against no published term at all	Not published on the product page	Limited lifetime against manufacturing defects Better
Weight (lb) Neither publishes a weight, which for two locks sold on how much steel they contain is a strange omission from both	Not specified by the manufacturer	Not specified by the manufacturer
Coupler Styles Proven publishes a coupler index and identifies fitment from photographs. Ft. Knox sells by coupler family with less guidance	Most trigger latch and thumb latch couplers. Separate models cover other designs — 2516-A for Atwood yoke latch, 2516-B2 for cast steel, 2516-AS for Airstream Better	Curt and similar couplers on bumper-pull trailers

Two different bets about what fails first

This is not two versions of one product. The companies have made opposite assumptions, and the whole comparison follows from that.

Proven builds the lock as one object. A welded or machined body with the puck integrated, and the cylinder specified when you order — Cobra tubular as standard, then Proven’s own disc detainer, then Medeco M3 or Abloy. The bet is that you decide once, correctly, and the lock is finished.

Ft. Knox builds the lock as a housing. The design is a surround hasp and puck lock reverse-engineered from the systems used on construction containers, where the hasp is structural and the puck is consumable. The bet is that the cylinder is the part with a service life — worn by weather, compromised by a lost key, or superseded by something better — and that you should be able to replace it without replacing the steel.

Both bets are defensible. Which is right for you depends on whether you think you will ever want to change the cylinder.

The cylinder arithmetic, which nobody puts side by side

Both brands advertise a base price that does not include the cylinder you actually want. They just present it differently.

• Proven ships the 2516 with a 7-pin tubular Cobra cylinder as standard. Its disc detainer is a paid upgrade, and Medeco M3 and Abloy cost more again. The same pattern applies to its PL-5 king pin lock, so it is brand policy rather than a quirk of one product.
• Ft. Knox sells the lock body and generally sells the puck lock separately, offering Trimax, Cobra-Sidewinder and Abloy Sentry cylinders in its own aluminum and steel puck bodies.

The practical consequence is the same in both cases: budget for the cylinder as a line item, and do not compare headline prices. A disc detainer resists picking and, where the discs sit deep in the body, drilling. A tubular cylinder is a lower grade. That difference matters more than any amount of steel around it, because ten pounds of body around a weak cylinder is a heavy lock rather than a secure one.

What each company is willing to publish

Documentation is where these two genuinely diverge, and each is strong exactly where the other is weak.

Published on the maker’s own pages	Proven	Ft. Knox
Material and grade	Yes — billet 6061 aluminum or 303 stainless	Welded steel, no gauge stated
Cylinder options	Yes, with a named ladder	Yes — three cylinder families
Cylinder replaceable later	No — specified at order	Yes — it is a separate puck
Fitment help	Yes — coupler index plus photo identification	By coupler family only
Warranty term	No	Yes — limited lifetime against defects
Weight or dimensions	No	No
Country of manufacture	Yes — majority USA	Not stated; company is Tulsa-based

Neither publishes a weight, which for two products sold substantially on how much steel they contain is a curious shared omission.

What owners actually say, and how much to trust it

The reason this comparison exists is that RV owners keep arriving at exactly this shortlist and then asking strangers to break the tie. Threads on several owner forums carry the same phrasing — people saying they have narrowed a coupler lock purchase down to these two brands and want to hear from anyone who has owned either.

Three themes recur in those threads. We report them as owner sentiment, not as testing, and none of it is something we or anyone else has measured:

• Proven locks are repeatedly noted as absent from the lock-defeat video compilations that circulate among owners, which readers there treat as meaningful.
• Owners of either brand generally report staying with it, and the complaints that surface tend to concern service and cylinder issues rather than a lock being defeated.
• The consensus, such as it is, is that both are well above the supermarket tier and that the choice is preference rather than a mistake either way.

Which to buy

Buy Proven if you want published materials, a cylinder ladder you can choose from, and real help identifying an unusual coupler — and you are willing to pay the upgrade so the cylinder matches the body.

Buy Ft. Knox if you want a cylinder you can swap later, a warranty term in writing, or you already run puck locks and want one key system across a trailer, a container and a job box.

Buy neither if your coupler is a common size and you simply want it locked. Both of these are premium purchases aimed at trailers worth protecting properly. A mid-price universal lock is the sensible answer for a light utility trailer, and the options are in our guide to the best trailer hitch locks.

Before you order either, identify your coupler — both brands sell by coupler design rather than by ball size alone, and what size coupler lock you need covers the three measurements that decide fitment. If you are protecting a fifth wheel rather than a bumper-pull trailer, Proven’s PL-5 appears in our king pin lock guide instead.

Questions worth answering