Description You need this screws to mount the base of Eames fiberglass chairs to the shock mounts (rubber disks) under the shell. Eames Plastic Chair Screws Metric Inch ThreadEames Plastic Chair Screws Metric Inch Thread Shell To Base Set of 4 screws for Eames chairs NEW Usual all Herman Miller and also early Vitra production (also with Herman Miller label) used inch thread, all Vitra production (in most cases labeled with a relief-like “V” underneath) need metric thread. Please make sure what you need, before ordering. Metric screws have 10 thread turns on 1 cm 12mm | 1/2″ for H-Base | Eiffel Base | Dowel Base 16mm | 5/8″ for For Tandem Bench and Office Chair base with Casters 18mm | 3/4″ for LaFonda Base Not sure if metric or inch? CLICK HERE A relief-like “V” underneath the seat shell in most cases need metric screws.