|Silicone||Good: Elastic. Allows you to stretch and pull over your head.|
|Wide connector tip||Good: Easy to slip onto the spectacle ends. Does not apply much pressure on the head.
Bad: May not be suitable for narrow temple which is less than 4 mm.
|Fixed length (180 mm)||Good: No need for adjustment
Bad: Need to check whether the length is suitable.
|NOTE: Not recommended for adult due to relatively short length.|
Silicone is elastic and an advantage of this strap is that it can be stretched and pulled over the head. For this product, the length is relatively short and since the length is fixed, it is more prudent to use it for children in case the length is too short for an adult. The slot at its ends is quite big and will be able to fit into most spectacle temple tip although it is probably too loose for narrow temples. Since the whole product is made of soft silicone, the slot walls are relatively soft and comfortable when pressed against the back of the head. It also helps that the slots are wide and flat so that the pressure on the head is low.
Given that this is a fixed length strap, there will be excess length dangling at the back of the head. If the spectacle is not sufficiently secure, the excess length may cause the spectacle to move when the child is running about. As the strap is relatively wide, it contributes to its overall weight and to spectacle movement if there is too much excess length. Once the spectacle is worn with the strap, the strap needs to be loose as any tension on it will pull the spectacle too close to the eyes.
This is a simple product to use and it is probably more suitable for use on children than adults. To ensure that this product works well on the user, it is recommended to check the suitability of its length using a string over the head.