Regarding ARMs:
A typical ARM in the US has a fixed rate period and an adjustable rate period, and most are based on a 30yr amortization schedule. So, there are 1/1 ARMs (1yr fixed, adjusts each year thereafter), 5/1 ARMs (5yr fixed, adjusts each year thereafter), 7/1, 10/1, and others. Some exist that adjust monthly instead of annually. 3/1, 5/1, 7/1 I think are relatively common.