You are watching 28 pin ZIF (Zero Insertion Force) sockets for use in any situation that removing an integrated circuit is more or less frequent. The sockets are New Old Stock in mint condition.The pins are thin as a regular integrated circuit so they can be inserted in any socket, although they can also be soldered.
I use this to quickly change the EPROMs in my drum machines (Drumtraks and Drumulator) but many other drum machines like Linndrum and LM-1 or Oberheim DMX will benefit largely with the addition of these sockets. I can also provide EPROMs for most drum machines. Common 28 pins EPROMs are 2764, 27128, 27256 and 27512.
Digidrums used this brand of sockets with their aftermarket EPROMs.
I am a synthesizer collector and technician, and I have over 100 synths - I am specially able to help in those that I have - you can check my collection in syhthechnics.com
Contact if you need help.