a body being tubular and having

an inner surface;

an outer surface;

a top;

a front end having an inside surface;

a rear end;

an opening being formed in the rear end;

a non-circular through hole being formed axially though the front end of the body;

a resilient element being mounted longitudinally in the body against the inside surface of the front end coaxially around the non-circular through hole and having

a side surface;

a front end being mounted against the inside surface of the front end of the body; and

a rear end;

a mounting hole being formed through the body near the front end of the body adjacent to a thumb depression; and

a button being mounted movably in and protruding from the mounting hole in the body and having

an inner end being mounted inside the body and abutting the side surface of the resilient element; and

a latching bar being formed on and extending transversely from the inner end of the button toward the rear end of the body and having

a middle;

a distal end being resilient, curving out and pressing against the inner surface of the body; and

a latch being formed on the latching bar near the curved end and protruding inward relative to the body;

a head being mounted coaxially on and protruding longitudinally from the front end of the body and having

a tip socket assembly being mounted coaxially in and protruding longitudinally from the front end of the body and having

a proximal end;

a distal end;

a mounting rod being formed on and protruding longitudinally from the proximal end of the tip socket assembly, corresponding to and being mounted in the non-circular through hole in the front end of the body and has

a distal end; and

a mounting hole being formed coaxially in the distal end of the mounting rod; and

a tip socket being formed coaxially on and protruding longitudinally from the distal end of the tip socket assembly; and

a mounting sleeve being attached securely to the front end of the body; and

a tip cartridge being mounted movably in the body, selectively extending from the opening in the body and comprising

a front end abutting the middle of the latching bar;

a rear end;

multiple clamps being formed around the tip cartridge and being resilient, and each clamp having a pair of protrusions;

a latch lip being formed on the tip cartridge near the front end to allow the latching bar to pass between the latch lip and the inner surface of the body and engaging the latch on the latching bar;

a central chamber being defined longitudinally inside the tip cartridge and having

a front opening being formed in the front end of the tip cartridge; and

a rear opening formed in the rear end of the tip cartridge;

a cover being detachably attached to the rear opening of the tip cartridge;

a central post being mounted slidably coaxially through the central chamber and the resilient element to restrict the tip cartridge to longitudinal movement and having

a front end protruding from the front opening in the central chamber and being mounting securely in the mounting hole in the mounting rod of the tip socket assembly; and

a rear end having two lips being formed on and protruding transversely from the rear end opposite to each other and selectively abutting the inner surface around the non-circular through hole in the body; and

a mounting bracket being mounted securely on the front end of the tip cartridge in the rear end of the resilient element and around the central post and having

a rear edge;

a central hole corresponding to and aligning with the front opening in the tip cartridge and being mounted around the central post; and

a flange being formed on and protruding radially out from the rear edge of the mounting bracket and abutting the rear end of the resilient element; and

multiple tips being stored in the clamps of the tip cartridge.