Hydor Theo Shatterproof Aquarium Heater, 100-Watt & Ideal For 14 To 26 Gallon Fish Tanks, 8.9-Inches Long (B00061UQ70)

Hydor 200W Submersible Aquarium Heater - Original Theo

Hydor In-Line External Heater - Original ETH 200 Watt 1/2

Hydor ETH 200 In-Line External Aquarium Heater, 200w, 5/8" hose - Original ETH 201,Black (B0002JEMMQ)

Hydor Theo Aquarium Heater, 300-Watt

Hydor ETH 300 In-Line External Heater 300w 5/8" hose

Hydor 50W Submersible Aquarium Heater - Original Theo

Hydor 400W Submersible Glass Aquarium Heater - Original Theo (B0006JLPFO)

Hydor 150W Submersible Glass Aquarium Heater - Original Theo (B0006JLPFY)

Hydor Theo Shatterproof Aquarium Heater, 25-Watt & Ideal For 2 To 7 Gallon Fish Tanks, 7-Inches Long (B0006JLPG8)

Hydor 7.5w Slim Heater for Mini-Aquariums and Bowls up to 5 gal

Hydor 15w Slim Heater for Bettas and Aquariums, 5 to 10 GAL (B006JVQ65M)

Hydor In-Line External Heater - Original ETH 300 Watt 5/8"

Hydor HYDROSET Electronic Thermostat with Display