- Ideally use with our Big Bore valve range for super simple pre ride sealant checks, just open the lever on the valve and slide the ‘Hey Dipstick!’ down the valve and inside the tyre. Then simply pull out and you can see the health of your sealant instantly. If it’s drying out or the level looks very low just add more sealant. If using a regular presta valve you can remove the core and carry out the same procedure. Make the ‘Hey Dipstick!’ part to your workshop tool kit - Stay ahead of pesky punctures and ride uninterrupted.