ASIC devices are designated for cryptocurrency mining. They have a much better hashrate to the energy consumption rate and outperforms GPU devices in this regard.
The Bitmain Antminer S15 (28Th) En.Sav. was produced by Bitmain and released in 2018. This miner consumes 850W, producing 17.0 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.