gstrek
Contributor
That's interesting, it appears there has been a slight redesign of the housing - I got mine in June 2018 and it has only one main o-ring, seated in a groove on the front part - the rear part is just flat and presses flush against the o-ring. It's difficult to tell from your photo, but it looks like they've added a protrusion to the back that extends into the front part, and has a second o-ring going around it - very similar to the older A6xxx housing with a fixed port. There is no mention of it on the website product pages, and I don't see it in their spare o-ring catalog either - must be a very new change.
Yes, the back has a protrusion that extends into the front part and has an o-ring. I like double o-rings similar to my first Olympus 5050 housing from 2003 time frame. I am very careful checking my o-rings each day for any stray hairs, lint, salt, etc. and so far all is good.
Do you use the Meikon silicone grease or something you can get locally? Seafrogs does not sell the grease but Meikon does. Meikon also charges nearly $20 US more than Seafrogs for the VPS-100, shipping is about the same.