The Allen Bradley push button contact block 800t is available online in a number of different styles and with prices ranging from $20 to $60.
Google Shopping offers the most extensive selection of 800t contact blocks online, but they are also available through Amazon Marketplace or through local distributors affiliated with Allen Bradley.
Allen Bradley is a brand-name for the equipment manufacturer Rockwell Automation. Rockwell Automation releases an online catalog with extensive information regarding the 800t units. The company notes that the 800t is designed for the most demanding industrial environments while remaining functional, rugged and attractive for a wide range of uses.