2012 MacBookPro and 2012 through 2015 iMac 27 in.

For 2012-15 MacBook Pro 13in. and 15in.

all models have 2 slots, each can take an 8GB module.

For 2012 through Late 2015 iMac 27 in

27 in. iMac has 4 slots, each can take an 8 GB module