Ilford HP5+ is one of the most notable black and white films in the history of photography, and that is not an exaggeration. It predates Kodak Tri-X by almost a decade. It has been on the market for close to a century in one version or another. It can be found in a variety of film formats to match nearly any film camera out there. It has a native speed of ISO 400 making it perfect for most lighting conditions. It has a classic grain, perfectly moderate contrast and excellent latitude. If you have never tried a roll, you should do so at your earliest convenience. It is the kind of film that you can spend the rest of your life invested in.
The 620 format shares many similarities with 120. The film and backing paper are identical with the only major differences being in the dimensions of the spool that 620 film is wrapped upon. 620 spools have thinner end caps, a smaller "keyhole" at each end of the spool and a thinner center column with a smaller circumference. These differences can prevent most 620 cameras from accepting film on 120 spools, and vice versa. No companies directly manufacture 620 format film anymore. Instead there are various sources which make 620 spools and then re-spool 120 film onto these spools.