Panerai straps can either come with a Spring Bar fitting or a screw-in Pin & Tube fitting. You need to measure the width of your strap (22, 24, or 26mm) and choose the right type of fitting, depending on your watch. You will receive 2 pairs of your choice, that is to say, you will receive fittings for 2 straps. Important sizing information/Springbars: their diameter (thickness) is Ø2.60mm, for all 3 lengths. Important sizing information/Pins & Tubes: Diameter (thickness) of the pins is Ø1.70mm and of the tubes is Ø2.60mm, for all 3 lengths. The lengths of the screw-in pins are 28.40mm (for the 22mm), 30.95mm (for the 24mm) and 35.50mm (for the 26mm).
Feel free to contact me for whatever questions you might have.