[CurlyDave]

I have an Addington hydraulic thumb for my Deere 110 TLB.

At the time I bought it, the word on TBN was that the Deere thumbs were soft.

I am very satisfied with it, and I believe they are available for the L-39.

A hydraulic thumb can do things a mechanical thumb just can't, although a good operator can work around some of that.

For my money, one of the biggest reasons to get a hydraulic thumb is safety. I know that I would be too lazy to reposition the TLB to change the thumb position, and the biggest uses for a thumb are in terrain which is very uneven and rocky or brushy. I just plain think the possibility of a fall in this terrain while dismounting and going out to reposition a mechanical thumb is fairly high.