Lock-Jaw Flex Collar

Name: Lock-Jaw Flex Collar
Brand: Lock-Jaw Collars
Rating: 4.83 (6 reviews)

The Lock-Jaw Flex is the flagship aluminum collar in Lock-Jaw’s lineup, built around two mirrored aluminum side plates joined at an intentional cutout that lets the body flex inward as the lever clamps down — the sleeve compresses around the bar instead of just pinching it. That design makes it the thinnest 2”/50mm Olympic collar Lock-Jaw sells, useful when sleeves are already crowded with bumper plates, and King of the Gym’s side-by-side test of the entire Lock-Jaw catalog found it the only model with zero measurable movement in both a static vertical-hold test and repeated drop tests.

A rubber pad protects the bar finish, and each collar carries a magnet for rack storage, though it’s mounted on a single face rather than the side — a placement multiple independent reviewers (Discovering Strength, Gym Crafter, King of the Gym) flagged as awkward, since the collar protrudes and can lose its grip on a rack rail rather than sitting flush. One-hand installation at light loads takes some grip strength since the sleeve wants to spin; it gets noticeably easier once more plates are loaded.

It sells for $59.95 directly from Lock-Jaw, making it one of the pricier options in their own lineup, and sits alongside siblings like Lock-Jaw Olympic Collars and Lock-Jaw Sport Collars as well as competitors like Rogue OSO Magnetic Barbell Collars 2.0. Reviewers and a steady stream of r/homegym owners calling it their favorite collar suggest the premium buys genuine holding power rather than just branding.

Colors	Black, Red, Grey, Blue, Gold
Sold as	Pair
Magnetic	Yes, single-face mount
Material	Aircraft-grade aluminum with rubber sleeve pad
Warranty	1 year from date of purchase (original purchaser)
Thickness	Just over 1" per collar (thinnest in the Lock-Jaw Olympic lineup)
Locking mechanism	Quick-release flex lever (mirrored side-plate design)
Compatible bar diameter	2" / 50mm Olympic barbell sleeves

What is a Collar?

What barbell collars are

Collars (clips) lock the plates onto a barbell’s sleeves so they can’t slide or rattle off — a safety essential, especially for pressing and Olympic lifts. The common types: cheap spring clips, quick lock-jaw / quick-release collars (the everyday favorite — fast and secure), and competition collars (precision-weighted, 2.5 kg each, for calibrated meets).

What to look for

A secure clamp that won’t creep under drops or high reps, quick on-and-off operation, and a fit for your bar’s sleeve diameter (standard Olympic is 50 mm). For most home gyms, a pair of lock-jaw-style collars is the right balance of speed, grip, and price.

How it compares

	Lock-Jaw Flex Collar	Lock Jaw Olympic Collars	Rogue OSO Magnetic Barbell Collars 2.0
GymRadar rating	4.83/5	4.57/5	4.47/5
Price	$59.95	$39.95	$65.00
Colors	Black, Red, Grey, Blue, Gold
Sold as	Pair
Magnetic	Yes, single-face mount
Material	Aircraft-grade aluminum with rubber sleeve pad
Warranty	1 year from date of purchase (original purchaser)
Thickness	Just over 1" per collar (thinnest in the Lock-Jaw Olympic lineup)
Locking mechanism	Quick-release flex lever (mirrored side-plate design)
Compatible bar diameter	2" / 50mm Olympic barbell sleeves

4.8/5 · 6 GymRadar reviews

Reviews by source

Expert	4.83/5	6 reviews
Youtube	4.6/5	4 reviews
Reddit	4.8/5	4 reviews

The Lock-Jaw Flex is Lock-Jaw’s flagship aluminum collar, and independent testing backs the marketing: King of the Gym’s side-by-side comparison of the entire Lock-Jaw lineup found it the only model with zero measurable movement across both a static vertical-hold test and repeated drop tests, and Garage Gym Life’s owner held a Steinborn lift to 405 lbs with no slip after weeks left loaded on a bar. Functionality is the standout dimension; build quality is the weakest — not because the aluminum-and-rubber construction is flimsy, but because the single-face magnet placement, flagged independently by three reviewers, makes the collar protrude and lose rack grip instead of sitting flush like competitors’ side-mounted magnets. At $59.95-$63 for the pair it’s one of the pricier picks in Lock-Jaw’s own catalog, but a steady stream of r/homegym owners naming it their “favorite” collar suggests the premium buys real holding power, not just branding.

+Functionality: benchmark holding strength — zero movement across both vertical-hold and drop tests, the only Lock-Jaw model to show none (King of the Gym)
+Functionality: held steady through a 405 lb Steinborn lift and weeks left loaded on a bar with no measurable slip (Garage Gym Life)
+Versatility: thinnest Olympic collar in the Lock-Jaw lineup at just over 1", useful when sleeves are already crowded with bumper plates (King of the Gym)
+Build quality: solid aluminum-and-rubber construction that protects the bar finish (Discovering Strength)
+Value: includes a rack-storage magnet and a 1-year warranty at $59.95-$63 (manufacturer; Garage Gym Life)

−Build quality: magnet is mounted on one face rather than the side, so the collar protrudes and can lose rack grip instead of sitting flush (Gym Crafter, Discovering Strength, King of the Gym)
−Functionality: one-hand install at light loads takes real grip strength and technique since the sleeve spins; easier once more plates are loaded (King of the Gym)
−Durability: independent testing so far tops out at a few months to about a year of use, with no multi-year wear reports yet (Garage Gym Life, Gym Crafter)
−Value: at $59.95-$63/pair it's the second-most expensive collar in Lock-Jaw's own lineup (King of the Gym)

$59.95

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