I opened the package no more than 15 minutes after purchasing the markers. The black one did not work at all. I guess I was lucky the blue green and red did but the writing was hard to read on the Zoom lesson I was giving. I should have returned them.
Works just fine. Except out of the package. Had to leave it with point down overnight. The next morning it worked just fine. Erases easily from my whiteboard and my laminated calendars.