Amazon.com: Acogedor Silicone Heater Pad 150 x 150mm, 12V or 24V 150W Flexible Silicone Heater with Back Adhesive for 3D Printer Large Print Bed, Adhesive Backing and NTC 100K Thermistor(24V 150W) :
24V 60W Silicone Heater Pad Heating Mat 100x100mm Heated Bed NTC 100K Thermistor - Walmart.com
24V 250W Silicone Heater for 235x235mm Heated Bed Upgrade Creality End