Comparison : Item # 7X00-XXX-BT, Ball Transfer Top Plate
Item # 7X00-XXX-DC, 30+ Hours Use with Integrated Recharging and HD Power Cord
Item # 57513-1, Replacement Battery Pack for AC/DC Units
Item # 7X00-XXX-E0, Ethernet Module, Lantronix Xport Module and Option Board Includes Software License and IP Address
Item # 7X00-XXX-SSR, (2) AC or DC I/O Solid State Relay