The Drop In Cores are ONLY COMPATIBLE with eco sabers, eco drop in switch sections 01 and 02, and the new apprentice asp switch-bodies. 

Drop-in cores are now available for individual purchase. Each drop-in core comes with a battery. Can be purchased with a standard or pixel blade.

RGB Core: 7.3" length / 0.9" diameter

Pixel Core: 6.2" length /0.9" diameter