Thank you for your question. Take a butter knife or flat head screw driver and gently press the tab on the light lens.

Thank you for your inquiry. There are two different lens styles for the model 678 and they are not interchangeable. Please check your label for the complete model including the letter which follows the model [678-A, B, C, D…] and contact our Customer Service Department at 800-558-1711 for the correct lens part number. They can also assist you with placing an order.