SageMaker studio: how to reference a specific model in the registry when running a batch transform job in another notebook

Question

I want to run a simple batch transform job. I have no end-point so can't use that method. If it was run in the same notebook in which the model was created, the code would be as follows:

transformer = xgb_model.transformer(
    instance_count=1, 
    instance_type='ml.m4.xlarge', 
    output_path=batch_output
)

transformer.transform(
    data=batch_input, 
    data_type='S3Prefix',
    content_type='text/csv', 
    split_type='Line'
)
transformer.wait()

How can I reference a specific specific model so it knows which one to use? Do I use model data loation? Reference the name directly?