These whiteboard erasers are firm to hold, lightweight and easy to use. They do not lose their magnetic attachment to the whiteboard, as I have used these for over 2 years. The only issue with them is that they are not easy to clean. It would be helpful if there was some type of cleaning attachment or rough surface on one end of an eraser so that you could rub one against the other to clean the residue/buildup. Having different colours is great, especially now since, as a teacher, we're not allowed to share any materials in these COVID-times.