A friend going to Cayman Brac Sept. 16th just stopped by with a new pair. I helped him set them up and play a bit (on land.)
The mount for either a 1" ball mount or YS style being forward with sensor toward the rear is a great improvement for easier fiber optic cord attachment.
The Inon S220 comes with two diffusers; a -0.5 "soft white" one losing 1/2 stop output and a practically opaque black one. That's supposedly -4.0 stops maybe for cutting down super close macro shooting? (I need to find and read the manual online.)
Without the bayonet attached -.05 "soft white" diffuser the little dome is a "fly eye" dispersion dome. Specifications show the strobe has a pretty good beam pattern. I recommended he use them with no diffusers for the slight power increase guide number of 22 over the previous Inon S2000 units (Guide Number of 20.)
I still use my 2 Inon S2000 units in single or dual depending how lazy I am that day
On my little Fantasea FG7X II housing for Canon G7X II and pop on "Air Lens" correcting for refraction I have 24mm focal length UNDERWATER. One Inon S2000 (and one Inon S220) mounted above in the cold shoe of my housing covers pretty darn well!
I use the Inon Shoe Base II which has a nice "tang" when tightened down preventing it from slipping off my housing's cold shoe.
I have found shooting compact 1" sensor cameras like Canon G7X / G7X II / G7X III or any Sony RX100 the little Inon S2000 or a new S220 provide plenty of power even for wide angle.
If I want DUAL coverage a lightweight tray and short handles with strobes flared out to send any backscatter AWAY from my lens works great too.
I regularly shoot ISO 125, shutter speed 1/200 and f-stop of F5.6 which on my 1" sensor camera is like f11 on a full frame sensor big camera.
Maybe for macro close to f6.3 - 8 max. Anything more just makes your strobes work harder or will require increasing to a higher ISO which I try not to do for better detail and dynamic range.
At retail of about $399.00 I think the Inon S220 will be a big hit. There's a bigger rear dial to bias either S-TTL (SLAVE TTL flash adjustment) or manual flash control plus bigger on / off switches.
Just one old guy's opinion that smaller is many times better!
David Haas