Polyester stacked metal film capacitor 0.39uF/50V, grid 5mm, +/- 5% tolerance
Label: 394J = 390000pF = 0.39uF

High volumetric efficiency
Low dissipation factor
Non-inductive construction
Operating temperature range: -40C to +85?C
Insulation resistance (25C): 1000MOhm
Self healing
Power rating: 50V
Grid: 5mm.