The CR1524a is the low-evaporation sandwich cover used for 24-lowwell MTPs. 

Other characteristics of the covers:

• The sandwich cover its function relies on the vertical force applied by a clamping system such as CR1801h
• Autoclavable and thus reusable many times
• The cover has a blue and green filter to prevent airborne contamination
• The 3m thick silicon layer is made from very durable rubber, which is free of any animal product