I tried these spotter arms with the S-4 Infinity squat rack, placing the 165lbs bar at the end of the spotters, and they tilted and fell down. So, they are compatible with Infinity racks, with the meaning that they can be installed on the racks, but the stronger the rack (I believe the fixed ones), the better. Whoever has S-4 independent stands, should use some counter-weights on the back side of the base, like I did in the picture attached, no problems at all after that. Otherwise the spotter arms are very strong and stay well in place, almost no need for the pins.

Bought this recently so I could set up my Rogue Y-1 yoke and use it for squats and bench. Super easy to put on and take off. Really helps me make the most out of my equipment. I absolutely recommend this for anyone with a Rogue Y-1 or Y-2 yoke if they want to use it for other exercises.

Just installed these on my S-4. First I tried some dips just to see how they would handle weight on the ends. I'm about 180 lbs and it quickly became apparent that they wanted to tip over (I suppose that if you were very controlled in your movements they might not). Then I installed them as low as they will go with the stands positioned for squats. 125 was fine at the end, but add a 45 and it instantly wants to tip over on the side with the additional plate. I threw a 45 on the back of each stand and it was able to handle 225 pretty securely. That's all the testing I was able to do with the weights I have now. So, these are a couple of the questions I'm left with: A. Should I buy more plates just to counter-balance this thing? I need more plates... to lift, not to counter-balance. B. Am I an idiot for not having started out with a squat rack? C. What did Rogue mean when they said it worked with S series squat stands? Maybe they meant you could install them... even if they don't really work. D. Why did some guy claim that it worked on his S-4s with 350 lbs in his review? That was the reason I went ahead and ordered these instead of cutting my losses and going for the rack.

Great product, only complaint would be you can’t these low enough for rack pulls, the bottom of the spotter arms hit the braces on the upright member of the rack

Attachments work great. I add them the half rack when I bench press or squat heavy. They feel study

Stable and easy to adjust. Safety Spotter are a fine add-on.

Well built, tough, reasonably priced. I use them as safeties when I bench press, and I can also rack my 12" log on them when I want to press out of the rack.

Spotter arms work great! I've used them to spot benches and squats.