Keep your CleanLight Hobby working as hard as your grow demands. UV-C lamps don't fail suddenly. They lose output gradually, dropping below the germicidal threshold while still appearing to work. A dimming lamp means less UV reaching mildew spores and botrytis on your plants. Regular replacement keeps your Hobby delivering the full dose your crop depends on. This is the official replacement UV lamp for the CleanLight Hobby (11W). Fit it in minutes and restore full protection. Available as a single lamp or as a 2-pack or 4-pack. A 2-pack saves $9, a 4-pack saves $37 compared with buying singles, and you always have a spare on the shelf when output drops. When to replace Replace your CleanLight Hobby lamp when either of the following is reached, whichever comes first: 8,000 hours of cumulative use Every 2 years, regardless of hours logged UV-C lamps degrade with age even when not in use. The 2-year rule exists because a lamp that looks fine can have lost significant germicidal output. When in doubt, replace it. What's included 1 × UV-C replacement lamp for CleanLight Hobby (SKU: A100103). The 2-pack and 4-pack contain 2 or 4 of the same lamp. Specifications Compatible with CleanLight Hobby (11W) Wavelength 254nm UV-C output at 100hr 3.6W Rated lifespan 8,000 hours Recommended replacement Every 2 years or 8,000 hours Add to cart and keep your Hobby at full germicidal strength. Ships with UPS (USA, Canada) or DHL (Europe). Free shipping on orders over $150; below that a flat shipping fee is shown at checkout.