Impervia LED Surface - 1200 x 600, IP65 Surface mounted luminaire with steel housing, white powder painted metal body, ABS frame with polyurethane gasket and microprism diffuser. Options: LE3 - Lithium Emergency (385 lumens output) LS3 - Lithium Selftest LA3 - Lithium Autotest S - Switch Dimming D - Digital Dimming (DSI) A - Digital Addressable Lighting Interface (DALI) C - Bi-Level Dimming (Corridor Function)* H - High Frequency Dimming (Analogue 1-10v) C83 - CRI 80, 3000K TRS - tamper resistant screws