Yenziwe ngejeli ye-silica, enokuvulwa okugobile okugoqiwe kanye nebhande eligudlukayo, okulula ukulifaka futhi elifanele ukusetshenziswa ezindaweni ezihlukahlukene.
Idizayini eqondile emelene nokushelela kwe-concave-convex ingavimbela ama-athikili ukuthi angasheleli futhi awe, amanzi asakazeke kuphedi elwa nokuchaphaza, futhi angakhipha amanzi ngokushesha futhi ahlale omile.
