I think these are the brand of drivers cutter went to in their kits........... not sure if they're using that model in particular but I'm sure @welight can answer questions for you on the brandWhat are peoples thoughts on these?
Pairui driver LGSU250-C1400D: $37.0usd/pcs
Efficiency of 90%
http://www.pairuigroup.com/upload/file/20160418/LGSU-250C.pdf