Double parton distribution functions (dPDF) represent a tool to explore the 3D proton structure. They can be measured in high energy proton-proton and proton nucleus collisions and encode information on how partons inside a proton are correlated among each other. dPFDs are studied here in the valence quark region. by means of a constituent quark model. https://allfixelectricales.shop/product-category/fork-crimp-terminals/