Black Bulb Pins Merchant and Mills Black Bulb Pins. £6.50 inc. VAT (where applicable) Out of stock. The bulb pin lets a tag hang tidily from a safety pin and is perfectly simple. 21mm long and like safety pins but with a wide bowl at the bottom for tags etc. Already pear shaped so nothing can go wrong. These make perfect stitch markers. Bulb pins are supplied in a smart green cardboard box.