69 kV-230 kV are referred to as âhigh voltageâ and voltages 230 kV-1,100 kV are referred to as âextra high. voltage,â with 1,100 kV also referred to as âultra high voltage.â The emphasis of this guide is on low and. medium voltage distribution systems.
Most manufacturers of umbrella strollers recommend that these strollers should not be used for any infant under 6 months old. This age is set by manufacturers because it is the average age when infants have sufficient strength to sit up and have some head and neck control.
At about age 6 months, infants can usually oppose the thumb in the grasping motion. Most infants can sit without support also around this age. By age 9 months, while sitting by themselves, infants should be able to self-correct posture when tilted to one side or the other, rather than just being tipped over.