About this 3D model

Holders for 18650 batteries. For balance charging or powering a load. Uses easly sourced parts. And is simple to print. Sketchup File included. 1, 2 and 4 tray holder. 4mm holes for M4 Hardware Springs : http://www.ebay.co.uk/itm/121197223478?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649