Mineral, as the German manufacturers, instrument glass, like the Chinese "Cosmos" and Anlida or Russian producers to eg La-Vie, acrylic – La-Vie. Some manage to insert a normal window glass, which is very dangerous in consumption. Safety is the best acrylic glass or, more understandable language, Plexiglas. Less of this glass – the absence of light, which gives the usual or mineral glass. Possible scratches over time, but the main plus is undeniable – unbreakable! Mineral glass is more resistant to damage in the form of scratches, does not have a large static (does not attract dust and atmospheric crumbs), but subject to the beating. Instrument glass produced specifically for the devices, has a good margin, but still subject to the beating. Alas, the glass arrows. Life battery is directly connected with arrows.
How? It's very simple – the more the weight of the shooter, the more effort is spent clockwork and the more starts to consume electricity. Therefore, the arrows are trying to do out of the lungs Materials: thin plastic (does not bend, it looks smooth, but breaks down) and aluminum (bend – the only drawback). It should take into account the weight of those who order watches for advertising with its logo. Not very useful would be if ordered the watch stops in a week, is not it? The only advice: buy electronic scales and discuss with the manufacturer. And do not chase the big, wide arrows at the top of the dial! Dial. Again, the selection criteria The first – the material.