A wafer container with a latch mechanism that provides sealing for large wafer containers, such as for 450 mm wafers, accomplishes secure door closing and latching with reduced torque requirements for rotating the central rotatable cam plate. In various embodiments, a camming slot formed in the rotatable cammed plate is arcuate and defined by opposing cam surfaces which are selectively engaged by a cam follower, such as a roller, attached to a proximal end of a latch arm. The roller can include unitary axle portions that snap into the proximal end of the latch arm and is supported at both axial ends of the roller. The proximal end of the latch arm can include parallel extensions separated by a gap, and have guide in surfaces to deflect the extensions as the axle portions of the roller are forced into position thereby seating the roller at both axial ends.