Do you know the development history of the manhole?

At first
The majority of decoration companies often ignore the quality of the access openings. The first common practice is to use wood or T-shaped keels to make the access openings on site. This approach causes the access openings to be easily damaged, cracked and deformed, and protruding from the outside (exposed access openings). Inconsistent, prolong the decoration period and affect the overall appearance.

Later Due to the continuous innovation of the market, some domestic manufacturers have made unremitting efforts for many years to use high-strength gypsum, glass reinforced fiber, and aluminum alloy as the base material to form gypsum inspection openings (industry name: gypsum double aluminum side inspection openings). The access port and the ceiling material form a perfect whole, unlike other access ports (holes), which have obvious connections and protruding that affects the beauty, it will greatly improve the grade and taste of the decoration effect, and fill the gap in the domestic market. As domestic mainstream decoration companies began to widely use finished product inspection openings, four mainstream inspection openings (aluminum alloy inspection openings, aluminum alloy composite inspection openings, aluminum alloy composite lower clamshell inspection openings, and wall inspection openings) were later derived according to decoration needs.