The Big Horn 19451 is a Pack of 100 Space Balls. Use Big Horn's inexpensive, genuine Space Balls to automatically center panels during the assembling process. They expand and contract with the wood to eliminate cracking of glue joints. Eliminates panel rattle. Space Balls fit snug, but not tight, by compressing 1/2 the diameter of the ball. 0.26-Inch diameter fits standard stile and rail. 8-10 Space Balls are recommended per door.