Watch List notes:

British Coins, Charles I, halfcrown, Tower mint, type 3a2, mm. triangle (1639-40), crowned figure of king on horseback l., shouldering sword, rough ground below, rev. oval, garnished shield of arms, reads MAG BRI FRA ET HIB (S.2776; N.2212), obverse very fine, reverse perhaps better
Estimate: 150-250 GBP