Watch List notes:

Lydia, Philadelphia. 2nd-1st centuries B.C. AE 17 (16.7 mm, 4.76 g, 12 h). Macedonian shield / ΦIΛAΔEΛ-ΦEωN, winged thunderbolt within wreath; monogram above. cf. BMC 1; cf. SNG Cop 342. VF. Scarce variety. 

This monogram is not recorded in the standard references.