Volatility-controlled indices featuring "intraday" data and mechanisms have become more popular as crediting options in fixed index annuities. But what are some of the details behind the marketing? We categorize intraday-based features into four categories that can help market participants better understand how these indices work and what to expect: intraday response, intraday rebalance, historical intraday models, and intraday risk premia overlays. Often used in combination, these features can help improve hedging efficiency and the potential for more index participation and better performance.