FRNIAMC Hydraulic Gas Lift Height Overal 18 Inch for Medium Height Stool Chair (Stroke 6.3 Inch)

i've ordered two of this same part now and i'm only using them for an office chair, no abusive treatment at all. i weigh 164 lbs. no one else uses the chair. i ordered this to adapt my standard office chair to a much taller drafting table. the first one felt slightly weak when you lifted the seat upward (not smooth) but otherwise, it functioned pretty reliably. not well, but acceptably for a cheap 3rd party replacement part imo. i disassembled the chair recently to swap out the base for a base with more adjustment functions. i used the (i think) standard method of removing the cylinder by tapping it free from the radial rolling base with a dead-blow and twiststed the seat free with an 18" pipe wrench and didn't notice any issues at the time. i did what i had to do to the chair and reassembled it using the same cylinder (the first extended one i bought here) and thought everything was fine until i tried to release the hydraulic pressure (aka lower the seat-height) using the intended lever. nothing happens, so this isn't really all that surprising, all cylinders fail like this or by blowing their seals and leaking the fluid out, eventually it's one of the two. I only got to use it for about a year and a month or so, which is substantially shorter than the average lifespan of most of the OEM cylinders that are shipped with chairs. still, i was okay buying a second one because it was like 16 bucks and i didn't expect it to be the last one i ever had to buy at that slightly questionable price. i was content with what i got out of it, if i had to be. second one comes in, i swap them out and within the first 24 hours (technically the second day, but well within 24 hours of first use) this thing needs to be manually pulled up while holding the base of the chair down with your foot as well as failure when it's lowering the seat and releasing pressure. unless you lean the chair around awkwardly until you find whatever position aligns the metal tubes up with the least amount of the slight bind that your weight causes. this suggests to me a possible issue with the tolerances of the parts (kind of unlikely) or just that the seals are leaking or are slightly undersized outright. there's a slight bit of oiliness on the tubes usually. much more than a good lift cylinder, but much less than one with an actually failed seal and not localized to the area of a single seal failure. i swear to god i'm not taking it out off-roading or anything. at any rate, i wouldn't want to waste these guys or my own time asking for a replacement because i have no doubt that every single unit they ship is a piece of junk. at $16.00 USD plus handling and tax added, then multiplied by 2, i could have spent roughly 8 dollars more and i would have been able to buy a quality lift cylinder and i'll bet you that even though whenever it DID fail like these two cheap ones; somebody else probably would've owned the chair by then. just buy a quality cylinder. i've never had a new one fail before these two. only ancient ones that have held up someone's fat butt for forty years really give anybody trouble. this is just a discount that you end up losing to an increased number of installations required and that another way of saying your chair was out of commission at multiple times. i can't remember ever really having to deal with that problem before, so i feel like these just tricked me into wasting my time a little.to be as constructive to the sellers as possible, since i'm not upset with them for anything... i suspect that the standard length replacements that they offer perform much more like the factory parts and these extended cylinders could quite possibly be prone to weakness because they're not engineered to support the same weight at the end of the extended height. probably should have increased the diameter of the cylinders to account for the additional flexibility of longer sections of tube or increased the wall thickness of the tubing at its current diameter. i would also suggest moving up to the next diameter of the rings or seals as well because the seals are also subject to increased pressures with the supported mass being held all the way at the very end of the cylinder's max travel. they probably won't bother to revise the product though, so i'd just advise buyer caution at least regarding the extra tall chair cylinders. you might end up getting what you paid for if you're not careful.

Bought some office chairs, but they were very low. Got these hydraulics and chair height is great now.

It was great for the first 2 months, but it recently started leaking for no reason. I bought this to replace my old one that had the same issue, except this lasted not even 1/5 of the time. Other than that, it was fantastic. Gunna weld it to its full height and just keep it that way. These things are super annoying to replace.

Did it’s job.

Replaced the lyft in my old desk chair, works even better than the old one ever did. It is taller than the old one which is perfect for my new desk.

Worked great to fix my racing style computer chair. Looks nice, works perfect. They offer different sizes so make sure to measure, the stock cylinder was too low so that was a nice upgrade.

I bought a open box chair from wayfair and it was missing this part. Ordered this and this was perfect fit.

Perfect replacement for my executive office chair. These are also easy to replace.

Lo difícil fué quitar el anterior pistón, estaba super atorado, pero le aplique WD40 y ya salió, también tuve que desarmar el cojín para golpear la parte de arriba del pistón viejo desde arriba con un desarmador de los que puedes golpear con un martillo.El pistón nuevo funciona de maravilla, lo volvería a comprar sin problema para mis demás sillas cuando lo requiera, al parecer el tamaño es estandar.

Lo usé para aumentar la altura de mi silla y hasta ahora todo bien, sin defectos ni cambios de altura inesperados