I've been using the Arc 20W panel along with V88 battery for a couple of years now, very happily. I recently acquired a second Arc 20W panel and am now using the splitter to run the 2 panels in parallel into the V88, essentially creating a 40W panel.
The splitter works perfectly and is of good build quality.
Incidentally, I had ordered 3 items in total which were shipped to me in London UK. Unfortunately a picking error must have occurred and one item was missing.
I contacted Voltaic to explain what had happened expecting them to offer a refund, but instead they shipped the missing item to me with no extra charge.
I have to tip my hat to you guys for that one.
Easy to use, great quality, does what it should.