Material: The O-rings are made of commercial grade rubber, typically Viton or FKM, offering good chemical resistance. Quantity: The package includes six O-rings. Function: These O-rings are designed for sealing applications in specific equipment. They are commonly used as small air cap O-rings. Compatibility: This part number is an aftermarket equivalent for the Graco 248131 O-ring and is compatible with various Graco Fusion (AP, CS, PC) and Probler P2 spray guns. Note: Users should refer to their equipment manual for detailed information to ensure correct fit and material compatibility for the chemicals being used. "A-Quality" O-rings are available from some sellers for the best chemical resistance.