Titanium is the way to go but for the price I'm a fan of Aqueon Pro heaters
They are black plastic no glass
Real durable, 2 color led
Cheap heaters are NOT the way to go though
I had a submersible heater, forget the brand, but it cooked a red eared slider almost
It made the water 145 degrees F
the turtle lived but was never quite the same after
Manufacturer actually refunded price of heater and $40 replacement of an adult turtle