ASIC
Application Specific Integrated Circuits (ASICs) are customized computer chips for Bitcoin mining. ASICs represent a x100 increase over FPGA (Field Programmable Gate Array) and uses less power.
Bitcoin ASIC miners perform complex calculations known as hashes, and each hash has a chance of yielding Bitcoin. The more hashes performed, the more chances the miner has of earning Bitcoin. Miners often find themselves joining forces (aka a mining pool) to increase their chances of earning Bitcoin.
ASIC Bitcoin miners review and verify Bitcoin transactions and create a new block so the information can be added to the blockchain. See mining for more information about that process.
References:
ASIC Miner Profitability: https://www.asicminervalue.com/
List of ASICs: https://en.bitcoin.it/wiki/List_of_Bitcoin_mining_ASICs