Watch List notes:

Time of Constantine X Monomachos (1042-1055) (?). Lead seal, c. half of the 11th century AD. Obv. Archangel Michael standing front, holding lotus-tipped sceptre and globus (cruciger?). Rev. St. Nicholas standing facing, wearing nimbus and holding book, raising right hand in blessing. To left, Θ/N[I]/K/O and to right, Λ/A/O/C. PB. g. 21.40 mm. 30.00 RR. Very rare and superb. Pleasant deep grey patina. About EF.

Cf. Elena Stepanova, 'The image of St. Nicholas on Byzantine Seals' in Studies in Byzantine Sigillography 9, K.G. JAUR, MUNCHEN-LEIPZIG 2006.