Square Lok screwdrivers, also known as Robertson screwdrivers, are designed for use with square-headed screws. They are particularly useful for several reasons:

• Strong engagement: The square shape creates a tight fit between the screwdriver and the screw head, reducing cam-out (the screwdriver slipping out of the screw head) and making it easier to apply torque.
• One-handed use: The square interface allows you to apply downward pressure without the screwdriver popping out. This is helpful in situations where you need to hold the screw steady with one hand.
• Reduced damage: The positive lock between the screwdriver and screw head minimizes damage to the screw head compared to flathead screwdrivers.

Here are some common applications for Robertson screwdrivers:

• Electrical work: Electricians frequently use Robertson screws due to the ease of one-handed use and the secure fit which helps prevent the screw from falling out while working overhead.
• Furniture assembly: Many RTA (Ready To Assemble) furniture pieces use Robertson screws for their ease of use and strong connection.
• Construction: Robertson screws are sometimes used in construction applications where a secure and tamper-resistant fastening is desired.
• Canada: Interestingly, Robertson screws are particularly popular in Canada, where the inventor, P.L. Robertson, is from.

Overall, square Lok screwdrivers, or Robertson screwdrivers, are a versatile tool for driving square-headed screws and offer advantages in terms of ease of use, reduced cam-out, and secure fastening.