Petzl highly recommends that the TIBLOC is used with round profile carabiners, but they suggest the hole on the S'MD carabiner (NOT round C-section) is for loss prevention of a TIBLOC. What
PETZL - Black Tibloc : Sports & Outdoors
Sm'D - Carabiners-And-Quickdraws | Petzl Other
Petzl Tibloc - Everything you need to know — Alpine Savvy
Karabiners and Quick Links - KOALA Equipment
Petzl Tibloc - Everything you need to know — Alpine Savvy
Sm'D - Carabiners-And-Quickdraws | Petzl Other
Petzl Tibloc - Everything you need to know — Alpine Savvy