Abstract: A staple for interlocking an engageable male part and a female part of a hose coupling. The staple has two tines which are insertable into two bores on the female part to seat within a groove on the male part when the male part and female part are engaged. The tines of the staple have an irregular cross sectional shape such that when the male and female parts and are biased apart, the female part bears against an outer region of the tines such that there is a resultant force which biases the tines into the groove, thereby making it more difficult for the staple to be unintentionally removed whilst the hose coupling is under pressure.