DXc Extension EN54-4 compliant PSU backbox increases the enclosure size of a DXc2, or DXc4 control panel to accommodate an additional pair of 17Ah batteries to provide increased system battery standby of up to 34Ah at 24V(depending o the batteries fitted in the panel) . This unit is supplied with the backbox, two cover blanks and an additional power supply unit (PSU). 263 x 390 x 147 (H x W x D)