JR Packages [P] Ltd. Offers Crush Resistant Corrugated Mailers. JR Packages [P] Ltd. Is an ISO 9001:2000 certified company. Crush Resistant Corrugated Mailers are the light-weight mailers which are perfect packaging solution for shipping small fragile items. Crush Resistant Corrugated Mailers are the one piece die cut cartons which fold together fast without the need for tape or glue.