The 1.5 ml polypro microcentrifuge tubes are available by the case of 1000 pieces (2 bags of 500). Offering easy identification, these tubes come in a variety of colors; amber, orange, green, blue, yellow, and natural. These tubes are also available to you in a rainbow pack totaling 600 pieces (100 pieces of each individual color). The microcentrifuge tubes have an attached lid providing a tight, leak proof seal, yet can still be easily opened. The lid is also of a uniform thickness to ensure trouble free piercing. All of these tubes feature a frosted writing area for labeling identification purposes, and have graduations.