Described herein is an LED module (500) comprising a PCBA (200) having an array of LED elements, a secondary lens array (300) and a lens holder (510). The secondary lens array (300) has a peripheral lip (360) and a plurality of boss portions (330a) which are compressed between the lens holder (510) and the PCBA (200) to form water-tight gaskets. The secondary lens array (300) also forms gaskets around wires connecting with terminal blocks on the PCBA (200) and effectively seals with a base plate (100) on which the PCBA (200) is mounted.