This light uses 4 lower powered LED bulbs as oppossed to one for the Seculite, though the overall light wattage is the same for both lights the illuminated area of the 4D is larger.  The 4D also has a stainless steel bar intended to protect the light in a rear end bump.  Designed to mount to a rear fender and requires two 5mm holes to be drilled into the fender–one on top of the other–20mm apart.

This and other fender mounted dynamo powered tailights should not by mounted on flimsy plastic fenders.  Metal fenders and plastic fenders with aluminum or steel reinforcements (such as SKS) will work fine.