Multi-purpose rack crossbar, multi-purpose rack crossbar device and sucker

A multi-purpose rack crossbar device, comprising:

• a multi-purpose rack crossbar, wherein the multi-purpose rack crossbar comprises:
• a rack crossbar body, and a first mounting component connected to the rack crossbar body;
• the rack crossbar body is provided with a first mounting groove and at least one second mounting groove, the first mounting groove is connected to a first end of the first mounting component, a second mounting component, wherein the second mounting component is fitted and connected to the at least one second mounting groove, and a runner assembly is provided at a second end of the first mounting component;
• wherein the second mounting groove comprises:
• a second opening portion and a second receiver which is connected to and wider than the second opening portion;
• wherein the second receiver comprises:
• a first rectangular portion connected to the second opening portion;
• wherein the runner assembly comprises:
• a universal structure consisting of a spherical structure and a third mounting groove fitted to the spherical structure.