diff --git a/main.go b/main.go
index 463e848..8856179 100644
--- a/main.go
+++ b/main.go
@@ -15,15 +15,12 @@ import (
 	openai "github.com/spideyz0r/openai-go"
 )
 
-const (
-	model = "gpt-3.5-turbo"
-)
-
 func main() {
 	help := getopt.BoolLong("help", 'h', "display this help")
 	apiKey := getopt.StringLong("api", 'a', "", "API key (default: OPENAI_API_KEY environment variable)")
 	temperature := getopt.StringLong("temperature", 't', "0.8", "temperature (default: 0.8)")
-	system_role := getopt.StringLong("system-role", 'r', "You're an expert in everything.", "system role (default: You're an expert in everything. You like speaking.)")
+	model := getopt.StringLong("model", 'm', "gpt-4", "gpt chat model (default: gpt-4)")
+	system_role := getopt.StringLong("system-role", 'S', "You're an expert in everything.", "system role (default: You're an expert in everything. You like speaking.)")
 	output_width := getopt.StringLong("output-width", 'w', "80", "output width (default: 80)")
 	delim := getopt.StringLong("delimiter", 'd', "\n", "set the delimiter for the user input (default: new line)")
 	stdin_input := getopt.BoolLong("stdin", 's', "read the message from stdin and exit (default: false)")
@@ -65,7 +62,7 @@ func main() {
 		if err != nil {
 			log.Fatal(err)
 		}
-		output, err := sendMessage(client, messages, float32(t), uint(w))
+		output, err := sendMessage(client, messages, float32(t), uint(w), *model)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -87,7 +84,7 @@ func main() {
 		stop := make(chan bool)
 		go spinner(10*time.Millisecond, stop)
 
-		output, err := sendMessage(client, messages, float32(t), uint(w))
+		output, err := sendMessage(client, messages, float32(t), uint(w), *model)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -96,7 +93,7 @@ func main() {
 	}
 }
 
-func sendMessage(client *openai.OpenAIClient, messages []openai.Message, t float32, w uint) (string, error) {
+func sendMessage(client *openai.OpenAIClient, messages []openai.Message, t float32, w uint, model string) (string, error) {
 	completion, err := client.GetCompletion(model, messages, t)
 	if err != nil {
 		return "", err