Lock-It Poly Pro 3" Strap BK

The 'locking' mechanism does seem clever. And seems to work. However, after putting it on and off a guitar twice, (and not with exccessive force, only as much as needed to put it on), the leather near one of the holes is already torn.
Also, I find the belt's material a bit rough. It is very broad, and I find that that causes it to excert a bit more pressure on my neck, which I do not find that comfortable. Maybe this is a matter of personal preference, however.

Don't change the originality of your guitar with clunky strap lock devices. These really work, are unshakeably safe and very simple to use. I have two, regular width for my 6 string and this XXL width strap with heavier gauge buckles for my headstock heavy 12 string. 2 days delivery to UK, Euro - £ exchange rate and keen pricing from Thomann. Excellent.

very large strap, very comfortable to wear for long period. the lock system is efficient, it might be a bit tricky to handle it the first time but it's fine.

Very good quality, comfortable to wear, wide enough to distribute the weight, locking system has not let me down yet and does not seem to do so any time soon. Very pleased with the overall quality. If anything maybe some would want to go with a strap with padding but I have not had any discomfort with using this.