Abstract: A separable fastener of the hook and eye type is designed to allow easy and rapid joining of the two fastener parts and to inhibit inadvertent separation of the parts after joining while nevertheless enabling the parts to be readily unfastened from one another when such unfastening is desired. Contributing to these results is the use in the hook member of a novel spring detent which yieldingly retains the eye member in its fully hooked condition with the hook member.