Excellent, heavy-duty, small collectors for field sampling or lab scale work. Collectors come in various sizes and mesh.WE NO LONGER INCLUDE THE BEAKER WITH THIS SIZE. BB-PC to BB-PC7 have permanent mounted screens of high grade polyester plankton cloth. To contain rotifers you would choose at 53µ mesh and for Artemia nauplii a 120µ screen is best. Our 8″ models, BB-PC8 to BB-PC13, feature a mounted rope handle.Please allow a week on larger sizes before shipment.