These 3D printed Turkish spindles from Turtlemade are fantastic. They are bottom weighted and tend to be very stable. On top of this, when you spin, you create a centre pull ball on the spindle itself, which you can then use to ply with, without worrying about winding the single yarn off for plying.
The spindle arms are made from PLA, which is a durable, biodegradable thermoplastic. Don’t worry! It only starts to biodegrade when exposed to extreme heat. Jen recommends that you don’t leave it in the car on a hot day. The shafts are made from molded ABS plastic, which is known for its impact resistant properties. Handy for a drop spindle!