Pack of 2 4011UB un-buffered NAND gate for Boss DR-55 and other similar machines that specifically require the unbuffered version. Devices are 'new old stock' and unused. Manufacturers include Motorola, Toshiba, On Semi etc. I will supply the current brand I have in stock.
I also have 4520BP counters and 5501P static ram ICs for these machines plus transistors and other parts in stock - contact me if you need anything specific for your DR-55.