The Spectra Air Cap is necessary for when a user wants to single pump.
Wasn't sure I needed these until I started single pumping on one side, and now the silicone cap seals tight every time. Getting two in the pack means I've got a spare when one goes missing in the diaper bag.
I lost the little stopper that came with my pump and these caps are the perfect replacement. The silicone fits snugly so nothing leaks, and having two in the pack means I keep one in the diaper bag and one at home.
Finally, a way to single pump without that awkward second flange getting in the way. The silicone caps fit snugly and are a total lifesaver when I'm just doing a quick session on one side. Really solid quality for the price, and the fact that you get two in the pack means I always have a clean one r