2-finger pocket is a fundamental training element for climbing in Frankenjura or Margalef :)
Each pocket has a super comfortable edge radius so your tendons are safe. But you fingers have to work hard.
We are using solid wood to make our holds, there is 1 hole for 5mm screw and 1 hole for M10 bolt plus a steel washer in each hole so the screws don't damage them. The screws come in perfects sizes with the holds, so you don't need to buy them extra ;)
Sizes:
L: 35 mm deep, 20° angle (0-30° overhang)
Screw size: 4,5 x 40 mm
Bolt size: M10 x 30 mm (not included)