I have 2 Jessem router table inserts and they are fantastic, bought them both in America which was a lot cheaper than over here.
They come with an allen key with handle and wind up and down very smoothly. with the marks around the slot where you raise it up and down you can be very accurate.
1/4 Revolution 0.016" 1/64"
1/2 Revolution 0.031" 1/32"
1 Revolution 0.062" 1/16"
2 Revolutions 0.125" 1/8"
4 Revolutions 0.250" 1/4"
8 Revolutions 0.500" 1/2"
I use the lift with a 3 1/2 HP Porter Cable 7518 router with the base removed and leave the motor mounted.
You can buy the bare motor with out the base from Eagle America and I think Rockler, as well as the Jessem router lifts.
I also use the Jessem router table top and the Jessem fence all are the best I have ever used, before that I used Wood haven products which again are fantastic but nowhere near as good as Jessem Products.
As with any table insert you can not just rely on the lift marks you still have to set with rule and the Jessem lets you lift and lower with one hand whilst holding rule to set height.
The lifts are a:
Mast-R-Lift Available in 9 - 1/4" x 11 - 3/4" or 8-1/4" x 11-3/4" plate sizes
and the Mast-R Lift FX in the same two sizes
In the Mast-R-Lift I have fitted the Porter cable 7518 motor mounted and the FX lets you put a smaller router motor into it both just lift in and out and are changeable within 10 seconds.
Look at the Jessem site you can down load the manuals for any of their products and you will see how good they are.
I also have the Jessem Table top and the Jessem Fence with the Mast-R-Slide which bolt on top of the fence but flips out of the way when not in use, and the Mite-R-Excel.
I urge you to check out Jessems web site,
www.jessem.com
Go on take a look