LEGO 1728 Crystal Crawler is a vintage Aquazone set from 1996 valued at $114 for new and sealed sets, up 1041% from an original retail price of $9.99. Annual appreciation has averaged 6.63% since release. On the used market, values range from $47 to $69 based on condition. Momentum for the set is level for now, with recent gains in value cancelling out slower growth than similar sets.
LEGO 1728 Crystal Crawler is an Aquazone Aquanauts set released in 1996, containing 97 pieces and 1 minifigure. The set builds a yellow Aquanauts sub with a blue cockpit, four propellers (two front and two rear), two robotic arms, and two wheels. It includes instructions for four alternate models. Also released as 6145 Crystal Crawler, this 1728 version is the same build but adds a plastic blue sea floor play stage.
Crystal Crawler has climbed about 6.6% a year since retirement and is worth around $114 sealed. If the forecast is right, it keeps going, to about $140 in five years. The average used price is $57 for those in good overall condition. New and sealed listings currently range from $139 to $175. Recent market trends show a period of price correction, with values declining over the past year.