A cutting tool includes a housing having a first end with a first edge and a second end. A handle extends from the second end of the housing. The housing has a slideable blade with a cutting position and a retracted position inside the housing. A finger portion is cantilevered from the first end of the housing. The finger portion and the first edge define an elongated opening having a juncture end at the first end of the housing. A cutting edge is embedded at the juncture end. The cutting edge is shaped, sized and orientated to facilitate forward slitting of heavy plastic sheet. The slideable blade slides axially along a track. A biasing means repositions the slideable blade from the cutting position to the retracted position.