Run-out groove etching used as catalog number, due to lack of any visible catalog number appearing anywhere else on the release. Matrix / Runout: TW-01 A1 (Side A Runout Groove Etching) Matrix / Runout: TW-01 B1 (Side B Runout Groove Etching) Matrix / Runout: TW-01 C1 (Side C Runout Groove Etching) Matrix / Runout: TW-01 D1 (Side D Runout Groove Etching)