I got this for the bottom of a deep pantry...I didn't want to be on my knees digging for cans of baked beans! It didn't need much assembly, just the sliders, the shelf and some screws, nuts, and washers.
The directions were minimal. You screw the sliders into your cabinet (4 screws) on the bottom, stretch the shelf to your desired width, and use the bolts/nuts to attach the drawer to the sliders (4 bolts/nuts.) Be sure to loosen the 4 additional little screws on the drawer when you try to stretch it, I didn't realize they were there (they were mentioned 3 steps later in the directions) and I was pulling like crazy to expand it...duh. Then you re-tighten them after the shelf is your desired width. The edges are not supported once expanded, only the middle has anything underneath it, I am not sure I would put anything especially heavy near the edges (especially if you expand it the whole way), but rather keep the really heavy things toward the center.
I was very careful aligning the sliders in the cabinet so it would pull out straight not skewed. It seemed simple enough, but when you attach the drawer to the sliders, you cannot get underneath the back 2 holes to hold the nut! Since the sliders don't extend the whole way, you have to sort of thread your fingers through the wire to reach under the bolt! I think you use the washers both under with the nut, and over with the bolt (it didn't say on the directions) but trying to hold the washer under the drawer AND slip on a nut was impossible for me, even with small fingers. I used a tiny bit of sticky-tak to hold the washer while I balanced the nut on my fingertip and slipped it underneath, then used pliers to hold the nut while tightening on top with a screwdriver. After all that finagling and dropping the nuts over and over, I got it installed in about 30 minutes. I took off one star only for the fact that it was difficult to attach the drawer/shelf in the back without access to the underside.
It didn't seem to slide as easily with the drawer attached as it did with just the sliders. I may have tightened the bolts a little too much and twisted the sliders in their tracks slightly. I will have to experiment to see what is tight enough to hold the shelf, but not too tight to torque the glides. It does slide though, just not as easily.
Overall the item is nice and substantial, not flimsy. It does sit off the bottom of the shelf about an inch or so (to accommodate the slider mechanism) so you lose a little vertical space. I can't complain too much about it as it serves a definite purpose, is nicely made, and really was not that complicated to install.
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Shelf on Wheels 89 Expandable Roll-Out Wire Cabinet ShelfProduct Description: Banish disorderly cabinets once and for all with this attractive, space-saving rollout shelf system. Made of heavy-duty wire and mounted on smooth-gliding wheels, the low-profile shelf accommodates most cupboards and cabinets and conveniently supports a range of household items, rolling easily beneath even the heaviest of loads. Use it in the kitchen to store nonperishable foods, stand mixers, and pots and pans, or in the laundry room or garage to keep detergents, cleaning supplies, or small cans of paint organized and simple to find. Expandable from 12 to 20 inches, the versatile unit requires no cumbersome sizing configurations or installation--just insert it into a pantry or cupboard, expand it to the optimal size, and fill it with frequently used products for convenience and ease. Ideal for reducing clutter and maintaining order, the rollout shelf system measures 22 by 12 (expanding to 20) by 3 inches.
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Since we renovated our kitchen we have become organization freaks. This product was a definite help. The under sink area used to be a mess with bottles of cleaner pushed to the back (and sometimes knocked over and leaking). The drawer allows you access to those items. 
