4 skewers, soaked in water 30 minutes if wood or bamboo
Preheat a grill for direct cooking over medium-high heat.
Thread the shrimp, sausage, tomatoes and okra onto 4 skewers. Set aside in the refrigerator while the grill gets hot.
Melt the butter in a small saucepan on medium-low heat on the stovetop, then add the garlic powder, seafood seasoning, salt, pepper and lemon juice.
Spray the grill grates with cooking spray. Place the skewers on the grill, then brush with the butter mixture and cook, turning once and brushing again, for 5 to 6 minutes total. Remove from the grill and serve immediately with lemon wedges.