Scroll wheel — Ratchet only is a normal notched wheel; Free-spin flywheel-spins for fast document scrolling; Free-spin + toggle switches between the two (a physical button, or Logitech's electromagnetic SmartShift that auto-shifts on a hard flick). Trackballs with a ring or twist-ball show as No wheel.
Multi-device = can you pair several computers and switch with a button? Multi-host rows list how many and how. Most gaming mice pair one dongle + Bluetooth but have no fast-switch, so they read Single host.
Side buttons counts thumb-side programmable buttons; MMO mice go to 12. Total is every programmable input.
Polling notes when a 4K / 8K rate needs a separate HyperPolling-style dongle.