I added on to one of my old custom blocks and made it into an extension with a single block. It converts a number of the specified unit into various time formats as text. You can use any positive number, and decimals are fine. For example, if you input 99.5, "s", "mm:ss:cs", then your output should be "01:39:50" (1 minute, 39 seconds, 50 centiseconds).