AVETCO technical diagram of a 13mm D-ring with outer dimensions 14.5mm by 17.7mm and inner 9.8mm by 13mm.

A schematic diagram by AVETCO showing a 13mm D ring with clear measurements Outer dimensions are 145mm L by 177mm W and inner dimensions are 98mm L by 13mm W The illustration includes directional arrows and an ID triangle for inner dimension marking