diff --git a/src/admesh/stl_io.cpp b/src/admesh/stl_io.cpp
index af9bb4f98..ddf377c78 100644
--- a/src/admesh/stl_io.cpp
+++ b/src/admesh/stl_io.cpp
@@ -151,8 +151,8 @@ bool stl_write_binary(stl_file *stl, const char *file, const char *label)
 	memcpy(buffer, &stl->stats.number_of_facets, 4);
 	stl_internal_reverse_quads(buffer, 4);
 	fwrite(buffer, 4, 1, fp);
-	for (size_t i = 0; i < stl->stats.number_of_facets; ++ i) {
-		memcpy(buffer, stl->facet_start + i, 50);
+	for (const stl_facet &facet : stl->facet_start) {
+		memcpy(buffer, &facet, 50);
 		// Convert to little endian.
 		stl_internal_reverse_quads(buffer, 48);
 		fwrite(buffer, SIZEOF_STL_FACET, 1, fp);