OK, I took a look at the strap that's on my StingRay, and I'm pretty sure it's an older version of a Levy's MSSB2-BLK. It could also be an MSS1. Although there are no model number markings on it, and it looks a little different to the ones they are making now, it looks in most respects identical. I bought this strap probably 20 years ago, so it's probable that the design has changed a bit since then. It measures 3.25" wide at the widest part, although the MSS2 and MSSB2 are listed as being 3" wide. There is an ever wider version available, at 4.5" wide, the MSSB2-4-BLK. That's what I would buy if I were buying today. I need to get out my Warwick and check that one, because it's similar, but a little different. That one has a velcro adjuster on it, I think?
Guitar - MSSB2-BLK
Bass - MSSB2-4-BLK
I got out my Warwick, and it has a Levy's MSS1Z strap on it, which is no longer made. It's somewhat fancier than the current MSS1, and as I said, it had a velcro adjuster and the tail end is black leather over black nylon webbing. The MSS1 is listed as 3" wide, as well, but the one I have measures, like my StingRay strap, a little over 3.25" wide, more like 3-3/8", but definitely not 3.5"
Guitar, Bass - MSS1-BLK
(update) OK, I found info about the MSS1Z on this Levy's Japan page:
LEVY'S OFFICIAL ONLINE | レヴィース・オフィシャル・オンライン
which lead me to believe both of my straps are MSS1 types, because the difference between the MSS1 and MSS2 lines are the type of leather.
MSS1Z:
(Google Translate, links below don't work): '
★
MSS1Z
This strap seems to be very popular with professional musicians.
It comes with the designation "LEVY'S brand and the length can be adjusted with Velcro", but
this model is exactly the strap for him.
★The adjustment part is Velcro, so it's quick and easy!
There are also
MSS1 with the same design but a slit type length adjustment part , and
MSS2 (garment leather) with a different type of leather. Garment leather is used for both pads.
It's simple, but it's a model with a good reputation for its solid construction. '