RCBS Reloading prime catcher rock chucker upgrade. Now catching the spent primers with this device will mean lot less mess dealing with the old primers and trays! You will probably love it so much you will throw away your old original primer tray! The collection tube has been designed to use a half inch I.D. tubing.(not included) This item is designed to only fit RC IV and Supreme The part can be locked into place with a empty .22lr shell (not included) With adjustment screw on the back to take up any fitment play. Credit for the design goes to thingiverse thing:#148190 by Icecil This part is 3d Printed by me, I can make as many as you like. See color options above. Bulk quantity pricing is available , just email me Note: Made with 3d printer so may have some small imperfections, but overall looks great Other model primer catcher available in my store. Thanks for looking