1. By using indexers we can read and modify the data present in private array. 2. Indexer enables objects to be indexed in a similar manner to array. 3. Get and set similar to properties. 4. ‘This' keyword is used to define indexers. 5. ‘value' keyword is used to define value to be assigned by set indexers. 6. Indexers do not have to be indexed by integer value. 7. It is up to you how to define specific look up mechanism. 8. Indexers can be override and overload. 9. Static indexers are not allowed. For similar kind of interview questions in c# you can refer this link c# interview questions