diff --git a/src/main/java/ca/tweetzy/auctionhouse/guis/sell/GUISellBin.java b/src/main/java/ca/tweetzy/auctionhouse/guis/sell/GUISellBin.java
index 7d41cff..de2c52f 100644
--- a/src/main/java/ca/tweetzy/auctionhouse/guis/sell/GUISellBin.java
+++ b/src/main/java/ca/tweetzy/auctionhouse/guis/sell/GUISellBin.java
@@ -44,8 +44,8 @@ public final class GUISellBin extends AbstractPlaceholderGui {
 
 	private final AuctionPlayer auctionPlayer;
 
-	private double listingPrice;
-	private long listingTime;
+	private final double listingPrice;
+	private final long listingTime;
 	private boolean allowPartialBuy;
 
 	public GUISellBin(@NonNull final AuctionPlayer auctionPlayer, final double listingPrice, final long listingTime, boolean allowPartialBuy) {