EVERBUILD® BLACK JACK® 903 BITUMEN TROWEL MASTIC is a trowel-applied, black, heavily-filled bituminous compound with added fibres for reinforcement. The product forms a surface skin, but the mass below remains soft to allow for moderate movement. Suitable for sealing and filling holes in mastic asphalt, roofing felt, corrugated iron, metal guttering and downpipes.