This part of ISO 11901 specifies the dimensions, in millimetres, nominal initial forces and type of gas springs. It applies to gas springs of type 900 to 100 000, pressurized with nitrogen with a nominal initial force of between 900 N ± 5 % and 100 600 N ± 5 %, for use in press tools. It also specifies marking, technical delivery conditions and designation. NOTE Specifications of mounting accessories for gas springs are given in ISO 11901-2.