M4 New Water Tight Lid with Super Wide+Thick Neoprene Seal (Fits All M4 Models) $4.99
New and improved Lid with super wide/thick neoprene foam gasket. Double acting seal is essentially leak proof. Includes a hyper flexible rubber lid vent to mitigate against tank vacuum during use, preventing tank "puckering". THE NEW XXL WATER TIGHT LID SEAL IS INCLUDED WITH THE LATEST M4 (AS OF SEPTEMBER 2019). UPGRADE LIDS WITH XXL LID SEALS ARE AVAILABLE ON WWW.MY4SONS.COM. THE XXL LID SEAL IS .75 INCHES WIDE AND REQUIRES THAT THE ORIGINAL LID BE MODIFIED TO HAVE THE INSIDE RIDGE REMOVED. SINCE THE NEW LID SEAL WILL NOT FIT INTO PREVIOUS LIDS WITH THE SUPPORT RIDGE THE XXL LID SEAL IS BUNDLED WITH THE MODIFIED LID.