Explosion-Proof Hand Chain Hoist From Which To Identify Quality?

Bought a new explosion-proof hand chain hoist main judge its quality from the following aspects:

1. explosion-proof hand chain hoist and load bearing chains, hooks and other bearing component in national standard safety timing under load will deform and crack and so on.

2. chain pull is smooth, no chain

3. lifting chain hoist in the process is running smoothly, no appear when lifting heavy objects appear only rises by

4. hook should be equipped with non-slip, off prevention device

5. gourd gear and the shaft due to quenching is not in place, causing broken teeth doesn't rise or fall

6. explosion-proof material shall be copper alloy material