I use whatever I have to write info down on. If I have a PCR then perfect. If not then I'll use a notepad, 4x4 (we carry 3x3 now), glove, arm, cloth tape, sheet on the gurney, etc.
I'm super awesome like flight medics. I like to have not one, but two strips of cloth tape. On both legs. Just in case you need to write down something. I also wear my sun glasses when it's either dark or inside. Because only the truly awesome people wear sun glasses at night.