This is a pocket size prop balancer that you can take with you when your are out on the field flying your RC plane or quadcopter. Measures 2.25" by 4". Update 2/27/2014 New update on the prop balancer. Now you only need to purchase magnets and some threaded rod to make. There is no need to hot glue in the magnets, just press them in. I also now made the hardware for the finger balancer from threaded rod and 2 #8-32 nuts. I bought a 12" by #8-32 threaded rod from Menards. It was a $1.70. See the instructions for the details on how I made the finger balancer. Enjoy and have fun!! 25% fill, 2 shells. You will need to purchase a finger prop balancer, magnets and screw. I just hot glued the magnets but you could superglue them in too. I have balanced 5x3 and 10x5 props on this. Bellow are the links for what you need to purchase. Prop balancer Fingertip Prop Balancer GPMQ5000 http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK247&P=FR&gclid=Cj0KEQiA6dGmBRC_3Mi-x_XywKsBEiQA1lcFP8iU0PXH9YzuApwIVhZIdO4lEK5IeKIzfW8XvM4uSKUaAtz_8P8HAQ Also found on Ebay. Magnets Neodymium magnets button 8mm x 2mm size.Update 2/27/2014 Cut a piece of threaded rod to 55mm and shape to a point on both ends on a grinder. I made some nuts that you will need to print out and tap out to the same thread #8-32. I designed the printed nuts to receive a #8-32 nut to be pressed into the end of the printed nut. I printed the part to be 50% fill, 2 shells and made from PLA. I've included some pictures of the final assembly. Let me know if you have any questions. Thanks.