the spring coil 16 in place and should a sprung band be utilised then a pivot pin 13 will pass through and hold one end of said sprung bands looped material in such a way as to provide the necessary push on the movable clamp towards the cord the upper part of the device is an upper assembly 26 comprising the push button 18 and plunger 23 the button 18 in part moves internally of the casing 3 and has an exterior portion which protrudes from the casing presenting the push button surface to be depressed with the button of preferably a solid square shape where the lower part of the underneath of the push button is shaped as a push rod plunger 23 which is either attached to or preferably part of the button moulding 18 the inner sleeve 20 of the casing 3 matingly receives the shoulder 21 of the button allowing the button 18 to travel up and down the guide 22 underneath the button is situated a coiled spring 19 located within a holding ring or groove 29 in both the button 18 and the casing 3 whereby the button 39 s push rod 23 is free to move up and down inside the spring coil 19 and through a hole 30 in the casing 3 between the upper assembly 26 and the lower assembly 25 in the resting position the spring 19 extends the button upwards to the point the internal shoulder 21 of the button hits the internal casing as shown in fig6 the push rod plunger 23 part of the button 18 is preferably of cylindrical shape with a rounded or wedge like angled strike face 24 having its edge facing in.