ISO Arms

Name: ISO Arms
Brand: REP Fitness
Rating: 2.72 (6 reviews)

The REP Fitness ISO Arms are modular, plate-loaded lever arms that bolt to the outside of compatible REP power racks, turning a rack into a hybrid cable-machine/ hammer-strength setup without adding floor space. Each arm moves independently through a full 180-degree arc on a bearing hinge, or locks in place for static moves like dips and pull-ups, and a built-in eyebolt lets lifters attach a belt- squat strap directly to the arm. Built from 3x3” 11-gauge steel with a black powder-coat finish, each arm holds up to seven 45-lb plates and comes in a 5/8”-hole (4000 Series) or 1”-hole (5000 Series) version to match REP’s rack hole pattern. Independent reviewers position it as a direct, budget-priced alternative to Rogue’s Monster Lite Trolley and Sorinex’s Adjustable Jammer Arms, at roughly a third to half their cost, trading some fit-and-finish and a clunkier pin-based height adjustment for a lower price and a couple of extra features (the permanent belt-squat eyebolt, full-length handle knurling) those competitors omit.

Finish	Black powder coat
Weight	66.2 lb (4000 Series) / 68.4 lb (5000 Series)
Material	3x3" 11-gauge steel
Hole size	5/8" (4000 Series) or 1" (5000 Series)
Max width	30.87" (including weight horn and handle)
Arm length	42"
Weight horn	2" diameter x 12.8" length
Manufacturer	REP Fitness
Compatibility	REP PR-5000, PR-4000, SR-4000 (not recommended for PR-4100); most 3x3" racks, unguaranteed on non-REP equipment
Range of motion	180-degree arc, lockable for static exercises
Weight capacity	Up to seven 45-lb plates per arm

What is a Rack Attachment?

What rack attachments are

Rack attachments bolt or pin onto a power rack or squat stand to expand what it can do — J-cups and safety arms/straps (the essentials), plus dip bars, a landmine, a lat pulldown, weight-plate storage, roller J-cups, and more. They turn a rack into a whole gym.

Compatibility comes first

An attachment must match your rack’s upright size (2x2, 2x3, or 3x3) and hole pattern/hardware (e.g. 5/8-in vs 1-in holes, Westside spacing). Attachments are usually series-specific — a Monster Lite J-cup won’t fit an Echo upright — so confirm the fit before buying.

How it compares

	ISO Arms	Monster Hip Thruster Bench	Rotator Voltra Add-on	Monster LT-1 50 CAL™ Trolley™ 2.0 & Lever Arm Kit
GymRadar rating	2.72/5	2.73/5	2.53/5	3.0/5
Price	$559.99	$330.00	$159.00	$1,230.00
Finish	Black powder coat	MG Black powdercoat
Weight	66.2 lb (4000 Series) / 68.4 lb (5000 Series)	36 lb
Material	3x3" 11-gauge steel
Hole size	5/8" (4000 Series) or 1" (5000 Series)
Max width	30.87" (including weight horn and handle)
Arm length	42"
Weight horn	2" diameter x 12.8" length
Manufacturer	REP Fitness	Rogue Fitness	Beyond Power
Compatibility	REP PR-5000, PR-4000, SR-4000 (not recommended for PR-4100); most 3x3" racks, unguaranteed on non-REP equipment	Rogue Monster Series racks/rigs only -- 43" upright spacing, 3x3" uprights with 1" hardware
Range of motion	180-degree arc, lockable for static exercises
Weight capacity	Up to seven 45-lb plates per arm

2.7/5 · 6 GymRadar reviews

Reviews by source

Expert	2.72/5	6 reviews
Retailer	4.4/5	104 reviews
Youtube	4.3/5	2 reviews

A budget-friendly plate-loaded lever-arm attachment for REP’s PR-4000/PR-5000 racks, and a direct answer to Rogue’s Monster Lite Trolley and Sorinex’s Adjustable Jammer Arms at less than half their price. Its standout dimension is value: independent reviewers call it “the best value jammer arms out there” for roughly $400 versus $995-999 for the name-brand alternatives, while still adding useful extras like a permanent belt-squat eyebolt and a fixed-position mode for dips and pull-ups neither competitor offers. The weak spot is build quality/adjustment — the fit-and-finish doesn’t match Rogue’s stainless-steel trolley system, and reviewers flag the pin-based height adjustment as clunky, with the ~65-lb arm assembly being awkward to reposition. GymRadar’s small owner sample (n=6) rates it notably lower on performance and value than the manufacturer’s own on-site reviews or the YouTube coverage — worth a discount given the tiny sample size, but a signal that satisfaction may erode with sustained use.

+Value: roughly $400 vs. $995-999 for Rogue's Monster Lite Trolley or Sorinex's Adjustable Jammer Arms while covering most of the same movements (Garage Gym Reviews)
+Functionality: permanent belt-squat eyebolt and a hitch-pin fixed mode enable dips, pull-ups, and triphasic training that neither the Rogue nor Sorinex lever-arm systems support (Garage Gym Reviews)
+Versatility: independent, plate-loaded arms support presses, rows, squats, deadlift variations, belt squats, and unilateral accessory work from a single rack attachment (BuyRightProducts; REP Fitness product page)
+Functionality: full knurling on the handle assembly and a corrosion-resistant chrome tube, both omitted on the Rogue and Sorinex competitors (Garage Gym Reviews)

−Build quality: powder coat and knurling finish fall short of Rogue's stainless-steel trolley system, reflecting overseas manufacturing at the lower price point (Garage Gym Reviews)
−Functionality: pin-based height adjustment only locks into two fixed holes rather than a continuous laser-cut scale, and the ~65-lb arm assembly is awkward to reposition without removing the handle (Garage Gym Reviews)
−Functionality: adjusting height/alignment between exercises takes noticeably longer than switching dumbbells, slowing fast-paced workouts (BuyRightProducts)
−Value: GymRadar's small owner sample (n=6) rates Performance 2.17/5 and Value 2.33/5, well below the manufacturer's on-site rating and the YouTube reviews (GymRadar)

$559.99

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