Eleaf GTL Atomizer Coil Head for TECC Eleaf iStick i40. GTL Resistance: 1.2ohm Power Handling: 7-13W. GTL Resistance: 0.8ohm Power Handling: 12-18W. GTL Resistance: 0.4ohm Power Handling: 20-30w. The coil is probably the most important part in Vaping.