Cateye loop 2 front rear set cateyes loop 2 front and rear lights are sleek and compact with eye catching visibility each light has 50hrs of flashing and 30hrs of constant runtime they both have a long onoff press in order to preserve battery life these lights are easy to install on bars with a diameter of between 22mm 32mm featureslong onoff pressdimensions 28mm x 28mm x 27mmlight source front white led x1light source rear red led x1battery cr2032 x2 per light runtime flashing