This model sinks without weights. 
 
This adult model is made of durable vinyl plastic with rust-resistant stainless steel skeleton, articulated joints, and optional CPR capabilities
When filled with water, CPR manikin will sink, a flotation device is needed
Includes 5 mouth/nosepieces, 5 airway systems, and shorts
Size: 65 in. x 23 in. x 9 in.  ( 165 x 58 x 23 cm )
 
Sh. Weight: 40 lbs. (18.14kg)