Hi again @Domcia.
With any solar safety film filter, they do need to be checked before each and every use for defects, i.e. pinholes, tears, etc... and if using glass solar filters, scratches as well. If you or your friend do see any, no matter how small... DO NOT USE IT.
Alternatively you can make on yourself for about the same price as the one you have shown. Also if the OTA includes a finderscope, you will/would need to make one for that too, or keep the end caps on it, or remove it and just aim for it. There a dedicated solar finders too. The one on my OTA is the TeleVue Sol-Searcher.
If you want to be safe then I would suggest investing in a Herschel Wedge, [only use with refractors], but you need to make sure it includes a built-in ND3.0 filter. Above is an image of my white-light solar setup - NOTE: the Herschel Wedge is nearest the camera.