Circular Fluorescent Tube Bulb 12W/T4 for Desk Lamp (VTLAMP10) : Amazon.ca: Tools & Home Improvement
Bulbrite F20T4 41K 20-Watt Linear Fluorescent T4 Bulb, 4100-Kelvin, Mini Bi-Pin Base, 20.5-Inch, Fluorescent & Neon Tubes - Amazon Canada
T4 vs T5 - Which Is Which?
Satco 13-watt Pin-based Compact Fluorescent Bulb - 13 W - 800 lm - T4 Size - Warm White Light Color - GX23 Base - 12000 Hour - 4400.3°F (2426.8°C) Color Temperature - 82 CRI - Energy Saver - 1 Each