21-day realized (annualized) volatility for BTC, ETH and the ETF wrappers — crypto vol runs structurally higher than any other asset class.
How to read Where each instrument's realized vol sits now (typically ~0.4–0.9 annualized for the majors). A present-state read of how much crypto is actually moving.
Realized (delivered) volatility only — the options-IMPLIED vol surface (Deribit DVOL, skew, term structure) is paid (Deribit's terms bar commercial use of derived data) and is deferred. Realized vol is not a forecast of future vol.