0.75" (19mm) D-ring

Print flat for optimal strength. The underside fillet might not print perfectly but it can be easily fixed in post. Pictured as used for hardware on a DIY packraft (1" version). For permanently sewn or welded-in fixtures that will be hard to replace, consider printing in ASA for durability if it's for outdoor use.

NOT for heavy load-bearing applications or life-critical uses.