The key features of a chit fund include:

1. Organized Structure:  Chit funds are typically organized by a registered entity (usually a chit fund company or cooperative society) that facilitates the process and ensures compliance with legal and regulatory requirements.

2. Chit Amount and Duration:  Each chit fund is structured around a specific amount (called the chit amount or corpus) and duration (called the chit period). The total corpus is divided into equal parts (units) based on the number of subscribers.

3. Chit Auction:  During each period, one subscriber is chosen through a process of auction (often called a 'chit auction' or 'chitty auction'). Subscribers bid for the right to receive the chit amount for that period. The highest bidder wins and receives the chit amount after deducting a predetermined commission (typically a percentage of the chit amount).

4. Rotation:  The process continues cyclically until all subscribers have received the chit amount once. For example, in a chit fund with 20 subscribers and a duration of 20 months, each subscriber would receive the chit amount once over the course of 20 months.

5. Benefits:  Chit funds provide a structured way for individuals to save and borrow money within a community or group. They are often used by individuals who may not have access to formal banking services or who prefer a collective savings approach.

6. Regulation:  Chit funds are regulated by state governments in India under the Chit Funds Act, 1982. The act provides guidelines for the registration, management, and operation of chit funds to protect the interests of subscribers and prevent misuse.

7. Risk Factors: While chit funds offer benefits such as collective savings and borrowing opportunities, they also carry certain risks. These include the potential for default by subscribers, fraud by organizers, and lack of liquidity if subscribers fail to honor their commitments.

In conclusion, chit funds serve as an alternative savings and borrowing mechanism that operates within a regulated framework. They provide flexibility and community support but require careful consideration of risks and adherence to legal requirements to ensure the financial security of all participants.