Customized version of http://www.thingiverse.com/thing:2104116

Created with Customizer! http://www.thingiverse.com/apps/customizer/run?thing_id=2104116

Fits perfectly for this Voltmeter:
http://www.banggood.com/0_28-Inch-2_5V-30V-Mini-Digital-Voltmeter-p-974258.html

I use this for quickly measure the voltage level of my 1s LiPos.

Using the following options:

board_slot_depth = 3
case_inner_height = 12
board_length = 10
board_width = 31
cap_Gap_width = 1.7
gap = 0.2
cap_gap_height = 2
USB_openening_width = 23.5
board_out_of_center_Z = 0
USB_openening_height = 10.5
board_thickness = 5