Nic salt base 20mg/ml or 10 mg/ml in Holland

Hi guys, i have moved to Nederland and i can’t find lirage size like 200ml bottle of flavourless nic salt base strength 10 or 20 mg/ml. I’m mixing it with my favourite aroma Maxx Blend. I don’t have any experience with nic salt booster or shots (not even sure what is called and what is difference)

I hope you have some advices and suggestions