Assuming you travel from Canada. Anything not for your own personal use is technically dutiable upon entry to Cuba.
Most of us Canucks just forget the “rules” since they fluctuate according to the aduana agent; whether some tourist previous to you pissed him/her off, the weather, the time of day, the price of food etc….... In short, forget trying to work it out.
I have taken all sorts of stuff, including lap-tops and hard drives, cordless phones, DVD’s, memory sticks, colostomy bags, pre-packed foods (can’t stand the stuff they serve in the hotels officer,) female hygiene items (currently in short supply,).......Im a male…....... you name it.
Just pack ‘em in your bag, and smile as you go through the aduana. They’re usually pretty forgiving to polite Canadians. If they inspect you and catch something, feign ignorance and smile again. Then tell ‘em it’s all for your own personal use, or your girl-friend’s grandmother who is suffering from malnutrition (a very possibe scenario.) If they don’t believe you, they will charge you duty. If you don’t pay the duty, they will take it off you, and offer to keep it at the airport for your return out of the country. For a nominal fee of course. Better luck next time.
I’m not being facetious; if you try to comply with ALL Cuban customs regulations you will go insane or travel with one small carry-on with personal essentials only.