... vibration, etc. b. Model Codes of Manual Molding Silicone Rubber HY-528# is applicable to make molds of smaller products and ... the production will be 2-3 pieces. HY-540#, compared to other two types, for its moderate hardness ... better quality & performance, its production will be 20-30 pieces. HY-570# is applicable to large size products duplications and Electronic ...