Thank you for viewing! This is a listing for a set of 4 JRC4558D dual operational amplifiers! They have been tested and are in working condition. These are from around the early 2000s. They were removed and stored after being taken out for modifications. 4558D 1214B x 2 4558D 1331B x 2 All ICs are used, but their operation has been checked using an IC check device (headphone amplifier). I have removed as much solder as possible, but some may remain. How about using these for the creation, modification, or research of distortion or overdrive pedals? Shipping will be via Click Post, wrapped in aluminum foil and protected with air cushioning. Thank you.