According to my experience these silicone protectors are a must-have for any 3D printing pen user... They fit snugly and securely over the nozzle, protecting both the pen and the user from burns. They're made from a high-quality, heat-resistant silicone, making them durable and long-lasting. The only downside is that they come in a limited range of colors, but that's a minor issue compared to the peace of mind they provide. Overall, these are a fantastic purchase for anyone looking to improve thSee full review