Extendible support leg

An extendable support leg comprising:

• a top leg tube (1), a middle leg tube (2) and an end leg tube (3) arranged axially telescopically and sequentially from outside to inside, wherein the support leg (10) comprises a first clamping mechanism (4) disposed between the top leg tube (1) and the middle leg tube (2), and wherein the support leg (1) comprises a second clamping mechanism (5) disposed between the middle leg tube (2) and the end leg tube (3);
• a locking control mechanism (6), comprising a locking ring (61) connected to the upper end of the top leg tube (1) and arranged to rotate circumferentially relative to the top leg tube (1), wherein the locking ring (61) is connected to the upper end of the top leg tube (1), wherein the locking ring (61) drives to extend into a drive shaft (62) in the top leg tube (1);
• wherein the locking ring (61) rotates circumferentially relative to the top leg tube (1) to move the middle leg tube (2) relative to the top leg tube (1) so that the drive shaft (62) is operably connected to the second clamping mechanism (5) to releasably prevent movements of the end leg tube (3) relative to the middle leg tube (2).