The material of the strap is durable. The bite of the buckle is quite strong (no slipping). The size is according to the chart (I usually have 32"/M, so I chose size "S" for 34"-37"). I'm still getting used to the awkward/weird buckle operation. A more traditional design keeps the entire base unit of the buckle flat against your body while you adjust the length and then just close the buckle cover. 3 of the buckle base unit itself, so you need to adjust the length/fit if the base unit is triangular/non-flat shape, then buckle it flat. (It's hard to explain this in writing unless you've buttoned it up, so it's always 1/4" and 1/2" looser than you just adjusted it, therefore, unless you're pulling it too tight on 1/4"1/2" when it's adjusted to fit just right when you buckle in. I don't recommend this off topic due to the uncomfortable buckle.