In order to distinguish between PVC and Hypalon, try the following:

1) Take a look inside of the tube through one of the valves. PVC is going to be the same color inside and out. Hypalon will be dark gray or black on the inside regardless of the color outside.

2) You can sand the material and find out what material it is made of. PVC will scratch and there will be no difference in color. Hypalon will produce dust and mat down when sanded..

3) You can also wipe over the material with MEK or Acetone. PVC will see some color on the clothe that you wiped over the material and the material will feel tacky. Hypalon will leave an oxidization and perhaps a little color on the clothe but the material will not be affected.