Made by Burr-Brown (BB), known as a high-precision operational amplifier. This is a set of two OPA627BMs, selected for their specifications, such as half the input bias current and one-third the input offset voltage compared to the OPA627AM. For product details, please see: https://www.digikey.jp/ja/products/detail/texas-instruments/OPA627AM/301328 You may find it helpful to look at the Digikey website. *About 20 years ago, when I was working for a manufacturer, I enjoyed DIY audio hobbies such as phono equalizers and DACs, and I purchased these through a trading company. [Quantity]: 2 OPA627BMs [Condition]: Unused [Included]: None (with delivery socket) [Application]: Modification and DIY of audio equipment, etc. ★Due to the prevention of product replacement, returns are not accepted. Please bid only if you agree to the above.