diff --git a/R/R7.R b/R/R7.R
index cec9070f4e..f84151afdb 100644
--- a/R/R7.R
+++ b/R/R7.R
@@ -132,7 +132,7 @@ length.R7 <- function(x) {
   tryCatch(
     x$length(), 
     error = function(err) {
-      cli::cli_abort("{.val length} is not support for objects with class {.cls {class(x)}}")
+      1 # when no custom length method is implemented, we return 1.
     }
   )
 }
\ No newline at end of file
diff --git a/tests/testthat/test-device.R b/tests/testthat/test-device.R
index c523af7e5c..5333f927b8 100644
--- a/tests/testthat/test-device.R
+++ b/tests/testthat/test-device.R
@@ -83,3 +83,8 @@ test_that("printer works", {
     print(torch_device("cpu"))
   })
 })
+
+test_that("can query device length", {
+  device <- torch_device("cpu")
+  expect_equal(length(device), 1)
+})