Arm module for a modular robot arm of an industrial robot, - having a first housing, a first connection side and a second connection side, - wherein the first connection side has a first connection plate and a first contact device, and the second connection side is mechanically co-rotationally connected to the first housing and has a second connection plate, - wherein the first contact device is arranged on the first connection plate and extends parallel to a first mounting axis, - wherein the first connection side can be connected to a further arm module of the robot arm, - wherein an optical signal and/or an electrical signal can be transmitted via the first contact device for data transmission, - wherein the second connection plate is embraced on the circumference by a securing ring, and the securing ring has an internal thread on an inner circumferential side, - wherein the securing ring is connected to a first housing of the arm module so as to be rotatable about the second mounting axis, - wherein first spur gearing is arranged on the first connection plate, - wherein the second connection plate has second spur gearing, - wherein the first spur gearing and the second spur gearing are designed to be complementary and/or correspond to each other, - wherein an external thread running around the first mounting axis is arranged on a first outer circumferential side of the first connection plate, - wherein the internal thread is designed to correspond to the external thread, characterized in that - the first connection side has a first fluid contact device, - wherein the first fluid contact device is arranged on the first connection plate and extends parallel to a first mounting axis, - wherein a fluid, in particular compressed air or a hydraulic fluid, can be transferred via the first fluid contact device, - wherein the securing ring is axially firmly connected to a first housing of the arm module. - having a first housing, a first connection side and a second connection side, - wherein the first connection side has a first connection plate and a first contact device, and the second connection side is mechanically co-rotationally connected to the first housing and has a second connection plate, - wherein the first contact device is arranged on the first connection plate and extends parallel to a first mounting axis, - wherein the first connection side can be connected to a further arm module of the robot arm, - wherein an optical signal and/or an electrical signal can be transmitted via the first contact device for data transmission, - wherein the second connection plate is embraced on the circumference by a securing ring, and the securing ring has an internal thread on an inner circumferential side, - wherein the securing ring is connected to a first housing of the arm module so as to be rotatable about the second mounting axis, - wherein first spur gearing is arranged on the first connection plate, - wherein the second connection plate has second spur gearing, - wherein the first spur gearing and the second spur gearing are designed to be complementary and/or correspond to each other, - wherein an external thread running around the first mounting axis is arranged on a first outer circumferential side of the first connection plate, - wherein the internal thread is designed to correspond to the external thread, - the first connection side has a first fluid contact device, - wherein the first fluid contact device is arranged on the first connection plate and extends parallel to a first mounting axis, - wherein a fluid, in particular compressed air or a hydraulic fluid, can be transferred via the first fluid contact device, - wherein the securing ring is axially firmly connected to a first housing of the arm module.