I don't know what warmth and thickness have to do with an aquarium heater. The heater works well but the instructions are not in English. However, it was still relatively easy to install and use. And came in a plain white box.
YukiHalu Mini Submersible Aquarium Heater With Thermometer And Temperature Controller - 25W, 50W, 100W, Or 200W Options For 5-40 Gallon Fish Tanks
25 Review
Tetra HT Submersible Aquarium Heater: Efficiently Regulate Temperature with Electronic Thermostat
9 Review
π Fluval E300 Electronic Heater - 300W Advanced Aquarium Heater for Tanks up to 100 Gallons (A774)
9 Review
Accumulative electric water heater Thermex Ceramik 50 V, white
11 Review
π U-BCOO Aquarium Gravel Cleaner Fish Tank: Manual Siphon for Efficient Filter Gravel Cleaning and Water Change in Tanks
22 Review
Steam cleaner Deerma Deerma DEM-ZQ610 EU, white/red
68 Review
Jasonwell Magnetic Aquarium Fish Tank Glass Algae Cleaner - Floating Brush (L Size)
37 Review
Mini pump Xiaomi Mijia Electric Pump 1S, plastic, black
55 Review