Housings for wiper seals are typically designed either as open (fig. 1) or stepped housings (fig. 2).
Wipers for open housings are bonded to a steel retaining ring and pressed into the housing. Therefore, they are called press-in wiper seals.
Wiper seals for stepped housings do not have metal components and can usually be deformed by hand for installation. They “snap” into the groove and, therefore, are called snap-in wiper seal.
For additional information about installation, refer to Installing wiper seals.