I would have to say my mask and my mouth piece on my regulator. My mask because I have a lot of hair and had difficulty find one that would keep a seal. This one is made in Italy and fits perfect..and it’s pretty! ha ha.. My mouth piece because I "surgically repaired" it to fit my mouth precisely! Makes for a great dive when you aren’t messing with plastic that is too large and digging into your gingiva..gum tissue.