A 30 millimeter plastic tension/ladder lock from YKK for all kinds of strap adjustments. This buckle goes with everything, because green is the new black.
Attach a strap to the buckle, and secure it with a tri-glide buckle. Put another strap in the tightening part, and tighten away. Done.
This buckle is made of polyacetal (POM), a thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. POM works exceptionally well in wet and moist conditions. The YKK product code for this buckle is LK30U.