When you are familiar with bitcoin investments you might have came across so called bitcoin doublers. For instance you invest 0.001 bitcoin and you get 0.002 bitcoin in return varying from a few hours and a week or so they claim. Several sites are reported as paying and indeed some are paying consistently. Unfortunately these doublers are not without dangers because some websites are too good to be true.

The information on the website

When you do a first check the websites often state that they have set up an automatically trading system using tradjng bots and that way they can generate these profits. Unfortunately there is no additional information how and where those bots operate. The other issue is that contacting the owners of website are very hard to reach and no information is given about the team. The other issue is that funds only can be withdrawn when the investments are expired. You have no control as long as investment is running. There are also doublers who are only paying a select amount which indicate that those payments onlu can proceed by taking funds of clueless investores

The real issue with those doublers

As everybody knows the supply of bitcoin is fixed abd no more than 21 mil can be mined this means that doubling is unsustainable long run and cannot sustain. The other issue is that most websites are running for a very short amount of time, which indicates thar those websites are likely to shut down pretty soon. Personally I have seen multiple websites disappear after a few weeks. When the websites disappear there is no way to send funds ftom that website wallet to your own. Then it is not your keys not your coins and you will lose funds that are active on the website. The goal of the website owner is to take all bitcoin after website went offline.
My conclusions and advice

The issue of the doubler scam is not that most websites will not pay, but that they will disappear after running the website with the coins. The best advice is to stay away from those webites or only invest in it with small amounts. It is likely those websites disappear and once offline means no way to transfer your funds. Do always your research first before investing. And be careful with crypto doublers most will disappear randomly.