While a nice piece of kit, the rubber O-rings that seal the cap & applicator needle react with certain solvents causing them to swell, screwing up the seal and making replacing the applicator needle into the cap after use all but impossible.
I tried it with Griff's Thin (my preferred and now discontinued brand) and Harry's Murray's head cement and it was a disaster. Dyna-King sent me replacement "non-reactive" O-rings, recommended smearing them with silicone or Vaseline but it didn't make any difference. I reluctantly returned mine for a refund since I don't use water based head cement or have any plans to do so.
Bottom line, Dyna-King and I concluded that it may be best to use ONLY with water based head cements, therefore I recommend it as an overpriced paperweight to keep feathers from blowing off of your tying bench.