Letter writing to prisoners is a poignant example of a mutual aid practice that offers support and connection to incarcerated individuals. This practice involves individuals or groups corresponding with prisoners to provide emotional support, maintain connections with loved ones, and offer a lifeline to those who may feel isolated. 

Its also vital for movements that have had many prisoners to support and stay in contact with them- not only to help the prisoners, but also because these prisoners can give important knowledge and advice from prison.