I own a Richbit RT-860, the supplied rear shock isn't up to the task of a rider plus any heavy gear being carried. After a lot of searching I found this product, I'd planned to max out with a 1100lb spring but couldn't get the right dimensions. Didn't have to worry. This product arrives with screws which are already laced with threadlock. The dimensions are exactly as stated on the webpage. I knew I was going to gain another 5mm in height, the bike expanded easily to take this. This was great as I'd put Rockshox TK 30 coils on the front and they did the same thing. Once assembled I tried it out, the lock out was fully engaged, I can't detect any downward movement at all when climbing on board which is really useful when load is max'd out. It isn't just a straight-forward on/off lock out either, it's variable. If you are looking to upgrade bike suspension for heavy pannier bags or a rider with a rucksack; or both. This is what you need. It really does the business.