Joytech 4.13'' (105mm) Diameter Spinning Top Base Crystal Glass Concave Mirror, Great High End Transparent Surface Double Concave Top Accessory DZ06

It is exactly as described. Nothing wrong, nothing wowing, you get exactly what you pay for.

This is exactly what it says a 100mm diameter concave on both sides glass disk just what i wanted for spinning a gyroscope and messing with light rays but the one i was sent has some chips in the edge not bad enough to ruin the function of the disk but still enough to show poor quality control

Worked well for a while, then broke when it fell from the desk onto carpet floor. Surprised given it was ~75cm drop and nothing protruding onto the glass. Oh well, wasn't expensive, it happens.

Just the right size and the concave glass is shaped well allowing tops spin smoothly towards the center. The build quality is fair, there are parts that look imperfect around the glass edges and brass framing, though isn't noticable unless looked closely. The glass could be a tad thicker, it does the job, but does sound a bit frail when the tops make contact. Overall good starter base for the money.

It works acceptably as a spinning top base, but the finishing on the edges of the glass is disappointing. In the pictures it looks smooth and minimalist, but in reality the edges are quite rough with some chipping and discolouration - nowhere near as elegant as advertised. Would suggest buying a vast from a more well-known brand instead…