I was looking for a fully submersible heater that is more rigid than the regular glass heater you can find at pet stores. A big plus is that the diving part is very durable. It also gets very hot (make sure it's fully submerged in water). So far, so good!
Accumulative electric water heater Thermex Ceramik 50 V, white
11 Review
YukiHalu Mini Submersible Aquarium Heater With Thermometer And Temperature Controller - 25W, 50W, 100W, Or 200W Options For 5-40 Gallon Fish Tanks
25 Review
π Fluval E300 Electronic Heater - 300W Advanced Aquarium Heater for Tanks up to 100 Gallons (A774)
9 Review
Faucet water heater with display
13 Review
Steam cleaner Deerma Deerma DEM-ZQ610 EU, white/red
68 Review
π U-BCOO Aquarium Gravel Cleaner Fish Tank: Manual Siphon for Efficient Filter Gravel Cleaning and Water Change in Tanks
22 Review
𧲠Efficient Magnetic Fish Tank Cleaner: KEDSUM Floating Clean Brush with Handle Design
34 Review
Vacuum cleaner TEQQO Aquastick 3 in 1 Power, grey/turquoise
26 Review