The $20 Picatinny riser, in 0.5", 0.75", 0.83", and 1.0" saddle heights and 3 or 13 slot lengths.

This is the plainest form a Picatinny riser takes: a slab of aluminum that lifts a rail-mounted optic an inch off the receiver so the sight picture stops feeling like a chin weld. The UTG Super Slim does that for about twenty dollars and does not pretend to do anything else.
Four saddle heights are offered, 0.5, 0.75, 0.83, and 1.0 inch, each in a 3-slot and a 13-slot length. The 0.83 inch 3-slot weighs under an ounce. Construction is 6061-T6 with a matte anodized finish, and the mount uses locking Torx screws with square integral recoil stops that index into the rail slots so it does not walk under recoil.
The honest limits: this is a riser, not a mount, so it raises an optic that already has its own base and it will not accept a bare Aimpoint Micro. And a $20 riser under a $600 optic is a false economy on a rifle that gets hard use. On a range gun, a .22 trainer, or a budget build, it is exactly the right amount of hardware.
Add the UTG Pro Super Slim Picatinny Riser Mount to your build and see how it enhances your platform.