GPU devices are very popular in mining cryptocurrencies but the ASIC devices usually outperforms them in many cases. The ASIC device usually consumes less power and has better hashrate.
The Canaan AvalonMiner 921 was produced by Canaan and released in 2018. This miner consumes 1700W, producing 20.0 Th/s of hashrate with the sha-256 algorithm, which makes this device almost (if not at all) useless. We do not recommend buying this device for mining nowadays.
The most profitable coins to mine using AvalonMiner 921: