3.5 cm ( 1.37″ ) and 4.0 cm ( 1.57″ ) thickness are most comment size standard for framed PV solar panels .
As a professional solar mounting parts and components factory, we have several types of end or mid clamps for your solar projects .

Please refer to our most common types as following :
For 35 mm thickness solar panels such profile below:

(1) T Shape Mid Clamp for framed solar panels 35 mm ( 1.37 inch ) in thickness

(2) U Shape Mid Clamp for framed solar panels 35 mm ( 1.37 inch ) in thickness;
(3) End Clamp for framed solar panels 35 mm ( 1.37 inch ) in thickness;
For 40 mm ( 1.57 inch ) thickness solar panels, such as profile below :

(1) T Shape Mid Clamp for framed solar panels 40 mm ( 1.57 inch ) in thickness;

(2) U Shape Mid Clamp for framed solar panels 40 mm ( 1.57 inch ) in thickness;
(3) End Clamp for framed solar panels 40 mm ( 1.57 inch ) in thickness
Welcome get more details from www.SolarPartsComponents.com for solar mounting clips .
Custom sizes for other solar panel thickness can be customized such as 20 mm , 50 mm …