A sliding sleeve or collar which is cylindrical and has an elongated guide or channel fluidly connecting the outer annular wall with the inner annular wall of the sleeve is disclosed. A connector having at least one open end and an elongated slot with a floor and a pin guide through the floor is further disclosed. The pin guide is open to the inside of the connector. Between the sleeve and the slot is a pin having a pin head visible through the elongated guide and two opposing spring arms of a size and shape to fit in said slot, and a pin body which movable fits inside pin guide.