Option quotes and the underlying price are supplied by Cboe and are delayed approximately 15 minutes. Curves are Black-Scholes theoretical values (r=3.75%, q=0) using the implied vol backed out of each leg's mid price; fills are assumed at the mid, with no commissions, slippage or assignment modelled. This is an educational modelling tool — not a quote service, not a broker, and not investment advice. Options carry substantial risk and you can lose more than you invest; read the risk disclosure before trading.