I've been diving for over 30 years and done over 1000+ dives to date. I'm a Dive Master with PADI. Finding a mask that fits and seals has always been a problem having a female, narrow face. I did a lot of research and ordered 6 different masks that got good reviews and supposedly were better fits for small to medium sized faces. Tested them all. When I saw the size of the Spectra Dive Mask I was sure it would be too big for me and not seal properly. Amazingly is sealed better than the smaller sized masks and provided a much larger field of vision to boot. The strap tabs were very easy to adjust unlike the old time ones which were a pain in the butt. I had a girl friend, who has a more squarish face, also test the Spectra Dive mask and it sealed so hard on her she nearly popped her eye balls out tugging on the mask to test the seal. I don't know how such a relatively large mask can seal this well on smaller faces. I suspect it would work well on medium and larger faces too because the skirt is so large. Maybe Scuba Pro uses better silicone or that double seal it has.Additionally, I tested the Cressi Big Eye that everybody raved about and the silicone skirt "fluttered" around my lower cheek when tested so that was immediately returned. I also tested the Sherwood Onyx Mask and the seal wasn't as good nor the field of vision. Then tested the slightly smaller Scubapro Synergy 2 Twin Scuba Diving Mask and the results were the about the same. It didn't seal as well when I smiled. All masks will leak a bit when you smile but IMO that is the real test of whether mask truly fits well. Then tested the Lince Mask which was supposedly designed for smaller faces. It fit but the field of vision was so limited it made me a bit claustrophobic - kind of like my old Riffe mask. I don't know the difference between the Spectra and the Spectra Tru Fit other than the latter is about $40 more expensive. Finding a mask that fits well it absolutely worth the effort and expense. Thank heaven for Amazon Prime!I plan to cough up the money and finally have this Spectra mask made into a custom prescription mask so I can see distances and see my dive computer. I'm having the work done by RXDiveMasks, Leonard Maggiore, Opticians, who invented the first Rx dive mask in the 1940s. Expensive? Yes. Very. But not just a luxury any more, but a necessity to read my dive computer. Older eyes just can't see those tiny dials any more. If my 1986 Orca Dive computer wasn't such a brick of a device I'd stick with it. It still works after 30 years!!!! If one doesn't need an Rx mask Amazon offers Rx masks for both near and far sighted people as much lower prices than a custom mask.