LEGO Transparent Light Blue Double Ball Joint with Ball Socket (90609)

LEGO Transparent Light Blue Double Ball Joint with Ball Socket has been used in at least 12 LEGO sets over the past 10 years, since it was first used in 2014. You can also find this part in at least 11 other colors. It has a design ID of 90609 which can usually be found molded into the bottom of the part.