A 365nm wavelength UV flashlight is, in most cases, the best option, optimally suited for UV resin curing. The 395-405nm UV LED lights that are now commonly used do not provide as much light in the wavelengths that best activate the resin. The Gulff 365nm wavelength LED produces a spectrum of light that best matches the absorption spectrum of the photoinitiator that is in most UV-curable resins. This is rechargeable and comes with batteries. This item must ship ground since it contains Lithium batteries. This may contain hazardous materials in California. Imported from Finland, these are designed to be used with Gulff resins.