Features:
This battery grip/holder is compatible with Nikon D7100.
Features shutter-release button, AE-L/AE-L button, multi selector, main and sub-command dials for shooting in a vertical position. 
Can hold one EN-EL15 rechargeable Li-ion batteries, 6 * AA batteries (LR6, HR, FR), effectively increasing the camera operating time.
Has a tripod socket. 

Specifications:
Item type: Vertical battery grip
Compatible with: For Nikon D7100 
Replacement: For Nikon MB-D15
Power source: 1 * EN-EL15 or 6 * AA batteries (not included)
Material: ABS
Operating temperature: 0-40 centigrade (32-104 fahrenheit)
Item dimensions: 142 * 51 * 78mm / 5.6 * 2.0 * 3.1in
Item weight: 273g / 9.6oz
Package dimensions: 15.5 * 12.6 * 9cm / 6.1 * 5.0 * 3.5in
Package weight: 356g / 12.6oz

Package List:
1 * Battery Grip 
2 * Battery Holder
1 * User Manual (English)