What's the best variable power supply?

How to Connect a Variable Power Supply to a Slot Car Track slot car track power supply In this video we discuss a wire harness that allows you to adapt a high output power supply to slot clube do porto Power Supply 5V 1A Battery 240mAh Lithium-ion battery Storage External Micro SD slot Expandable upto 1TB storage Operating temperature -5℃ to 65℃

slot 24h Koford Digital Top of The Line Power Supply M325J M325J Digital switching power supply for cool operation with motors which pull high current at low voltage