We propose an observable sensitive to transverse momentum dependence (TMD) in , with defined purely by lab-frame angles. In 3D measurements of confinement and hadronization this resolves the crippling issue of accurately reconstructing small transverse momentum . We prove factorization for for with standard TMD functions, enabling to substitute for . A double-angle reconstruction method is given which is exact to all orders in QCD for . enables an order-of-magnitude improvement in the expected experimental resolution at the EIC.