LAM: Legend arranged in circle; triangular point between letters; beaded border.
Reverse
LAM: Legend arranged in circle around central pellet; triangular points between letters; L retrograde.
Reference
Dissard, P. 1905. Collection Récamier. Catalogue des plombs antiques (sceaux, tessères, monnaies et objets divers), Paris and London: Rollin et Feuardent, https://zenon.dainst.org/Record/000740205
Mitchiner, M. (1984). Rome: Imperial portrait tesserae from the city of Rome and imperial tax tokens from the province of Egypt. Numismatic Chronicle 144: 95-114.
Lang, M. and M. Crosby (1964). The Athenian Agora X: Weights, Measures and Tokens. Princeton, New Jersey, The American School of Classical Studies at Athens. (https://zenon.dainst.org/Record/000211771)