The Crk phospho-regulation antibody sampler kit can be used to detect phosphorylation of Tyr-221 and Tyr-251 in Crk II, as well as phosphorylation of Tyr-207 and Tyr-251 in CrkL. The kit includes a rabbit polyclonal anti-CrkL and mouse monoclonal anti-Crk II antibody to detect Crk expression levels.