From Whip Mix website:
ISO Type 4
Snap-Stone is an exceptionally fast setting stone with an early high compressive strength, which allows separation of the cast from the impression in 5 minutes. Because Snap-Stone is fast setting, hand mixing is recommended. Snap-Stone is compatible with all impression materials and its versatile, light pink color makes it suitable for many uses.
Physical Properties:
Water/Powder Ratio: 23 mL/100 g
Working Time: 60-90 Seconds
Setting Time: 2 minutes
Setting Expansion: .15%
Compressive Strength, Wet (1 hour): 6,000 psi (41 MPa)
Compressive Strength, Dry (48 hrs.): 14,000 psi (97 MPa)