Pride PR8500 21S 8500 Soft Close Undermount Slide, Size 21", Price/Set

There is definitely a learning curve to installing these slides but they work very well.

It is very strong and comfortable

Heavy duty slides, easy to open and close. They’ve been supporting my trash can drawer for over a year now

I would say these are really best used with an overlay style drawer, however I did manage to use them in my van build using aluminum extrusion and a full inset drawer. The holes line up with 2040 aluminum extrusion for anybody doing a van build. I use five millimeter by eight millimeter bolts. You can either mount these on the side only, or alternatively use the L bracket (supplied) and mount/secure in the back. Since I was installing in a van that had a curved wall I opted for the side mount. One person mentioned the instructions were bad. I agree the written instructions are next to impossible to read. I watched the manufacturer's video and took some screenshots of key measurements. The clearance on the sides is pretty much the same as side mount drawer slides.--about a 1/2". The bottom of your drawer needs more than the normal amount of space if you want to do a full insert. You still need a fair amount of space regardless compared to a side mount. It's all outlined in the install instructions. You do have to build your drawers to the slide and plan ahead. There are some unique requirements for these slides. I have this style drawer slide in my high-end kitchen cabinets in my house. Super smooth, and the self-closing feature is extremely nice. Very quiet. I would not hesitate to buy them again even though they are a bit expensive. They are well-made and worth the money. The one nice thing about a bottom mount drawer slide is you don't need to worry if your cabinet sides are bowed or your drawers warp. It's amazing how many times plywood will bow after you cut it. There's not a lot of wiggle room with side mount drawer slides. I have spent many hours shimming, adjusting and readjusting, and that's just not an issue with these slides. As long as these remain parallel to each other you are gold. I think they do allow for about two-millimeter adjustment both in height and width. The packaging was very good as well.

Very nice heavy duty tracks works perfect on my shelves that slide out

I definitely recommend these drawer slides for their strength and durability. I repurposed them as a sliding shelf for my home theater amp which weighs almost 50 pounds. The slides were easy to install and slide perfectly even with all that weight.